CHAPTER I

  1. INTRODUCTION
    1. Introduction

Palm oil is one of the major fats and oils produced and traded in the world today. It forms an important ingredient in the diet of many people in all over the world (Tagoe et al., 2012). Palm oil which is orange-red to brownish or yellowish-red in colour is extracted from the fleshy mesocarp of the fruit of oil palm tree (Orji and Mbata, 2008). Elaeis guineensis is the genus of oil palm tree and it is a monocotyledon. The highest oil producing plant is oil palm tree. Two types of oils are produced; these are palm kernel oil and palm oil. Palm kernel oil is obtained from the endocarp while palm oil is obtained from the fleshy mesocarp (Ekwenye and Ijeomah, 2008). It is rich in Vitamin E (tocopherols and tocotrienols), corotenoids and phytosterols (Sundram, 2003). Palm oil is used in cooking and for the manufacture of soap, margarine, grease and candle, while palm kernel is edible and has a pleasant flavour when eaten raw.

An average fruitful life-span of oil palm tree is about 25 to 30 years. It can reach a height of up to 30 feet and produces fruit bunches from three years of age after field planting. In each productive year, an oil palm tree may produce between 8 to 12 bunches of fruit. Each bunch weighs between 10 and 25 kilogrammes and contains between 1,000 and 3,000 fruitlets. Loose fruits are ripe fruit lets which have fallen from a ripe bunch. They are often used as an indication to measure bunch ripeness. These fruits are the ripest in the bunch, and therefore they contain the highest amount of oil. The oil palm fruit is almost spherical in shape. It consists of a hard seed (kernel) enclosed in a shell (endocarp) which is surrounded by fleshy husk (mesocarp) (Source: MPOB).

In oil palm (Elaeis guineensis Jacq.) fruit bunches, the fruitlets do not ripen simultaneously: owing to slight variations in the time of pollination. The fruit ripen first on the bottom, and the ripening ‘front’ progresses towards the top of the bunch (Sambanthamurthi et al., 2000). This asynchronous ripening affects the quality of extracted palm oil. The oil palm is a monocot fruit subject to climacteric ripening with high amounts of lipids accumulated during fruit maturation (Ohlson 1976; Tranbarger et al., 2011). In oil palm industry, there are various steps involved in the processing crude palm oil from field to mill including harvesting, transportation, reception of the raw material, sterilization, threshing, fruit digestion, pressing, clarification, drying and etc for crude palm oil (CPO)( Nualwijit and Ladawan, 2014).

Harvesting involves the cutting of the bunch from the tree and allowing it to fall to the ground by gravity. Fruits may be damaged in the process of pruning palm fronds to expose the bunch base to facilitate bunch cutting. As the bunch (weighing about 25 kg) falls to the ground the impact bruises the fruit. During loading and unloading of bunches into and out of transport containers there are further opportunities for the fruit to be bruised. The field factors that affect the composition and final quality of palm oil are genetic, age of the tree, agronomic, environmental, harvesting technique, handling and transport.

Fats and oils are graded by their acid and free fatty acid (FFA) contents, which are used as an index to determine their quality (Kardash and Tur’yan, 2005). The major fatty acids predominant in palm oil are oleic and palmitic acids (Salunkhe et al., 1992). Fatty acids play a very important role in fats and oils because of their health implications in the human diet and properties in industrial processes. The type of fatty acid determines the nutritional status and storability (keeping quality) of the oil. Palmitic acid increases in palm oil are mostly associated with oils produced from over-ripe, bruised and crushed fruits, fruits subjected to severe impacts from loading and off-loading bunches and oils stored over long periods (Salunkhe et al., 1992; Tagoe 2008). Enzymes which are in adipose tissues comes out with the cell damage and they break down the glycerides in the mesocarp into glycerol and as FFA. The Autocatalytic hydrolysis of the oil in the presence of moisture also increases the fatty acid content (Purseglove, 1975). Free fatty acids in oils and fats may also be caused by the action of microbial lipases (Odunfa, 1989).

To maintain the quality of the raw material, care is needed during and after the harvesting of oil bearing fruits that are perishable and susceptible to fat breakdown. Bruising of fresh palm fruits accelerates lipase activity leading to fat degradation. Oil bearing crops such as oil palm are prone to mould infestation during storage. Palm is sterilized as a first step in processing. Adipose tissues and fish-based raw materials (that is, the body or liver) are rendered within a few hours by boiling to destroy enzymes and prevent oil deterioration (Source: www.fao.org)

CPO contains 49% of saturated fats and 46% of unsaturated fats and from the unsaturated fats, 9% is polyunsaturated and 37% is monounsaturated. It contains palmitic, myristic and stearic acid as saturated fatty acid and oleic, lenoleic can be considered as unsaturated fatty acid. From those fatty acids, palmatic acid percentage is around 43% from the fatty acid of the CPO (Source: MPOB). When considering quality standard, FFA% should be below 5% as well as cumulative moisture and dirt content should be below 0.5% in CPO (SLS 720). According to the industrial quality standard dirt content should be below 0.2% and moisture content should be below 0.3% in CPO.

This study was done to identify the Effect of postharvest handling operations of oil palm fruits on quality of CPO based on FFA and moisture percentage. Factors which were considered for the study were handling due to transportation, storage period, fruit damage and interaction effects of those factors. Two factor factorial complete randomized design (CRD) was used to analyze the data.

    1. Objectives
      1. General Objective
  • To study the effect of post harvest handling operations during fresh fruit bunches (FFB) of oil palm fruit processing and maintaining quality standard of the CPO

1.2.2 Specific Objectives

  • To determine the effect of storage period of harvested oil palm fruits on FFA and moisture level of CPO
  • To identify the effect of handling in transportation on quality of CPO
  • To determine the effect of fruit damage on FFA level and moisture contents of CPO

CHAPTER II

LITERATURE REVIEW

2.1 Quality of Crude Palm Oil (CPO)

The quality of oil could be assessed by measuring the amount of free fatty acids (FFA), dirt content and its moisture content. The internationally-accepted quality standard on the basis of FFA is 5%, dirt content is 0.2% and moisture content is 0.3%, with penalties for exceeding these percentages. The FFA content of mature fruits intact on the bunch is on the order of 0.01% (NIFOR, 1989), but when bruised and crushed fruits are processed, the FFA content increases rapidly. It was also noted that palm fruits are particularly susceptible to deterioration and that the lipolytic enzymes are so active that even under the most favourable conditions, palm oil seldom has FFA content up to 2-3%. Under crude conditions of processing, the FFA content may range between 20% – 60% or even more.

NIFOR (1986) found that the quality of oil produced depends to a large extent on the correct timing of the harvesting. The best time to harvest the fruits is when they start to loosen and can be dislodged. This is often indicated by the presence of 2-3 displaced fruits on the ground at the base of the oil palm tree. If harvested earlier, the fruits will not have attained their full oil content, resulting in oil of low quantity. If harvested too late, the FFA content will be high and as a result of this, quality of the oil will also be poor (Jimoh and Olukunle, 2011).

Fats and oils are graded by their acid and free fatty acid (FFA) contents, which are used as an index to determine their quality (Kardash and Tur’yan, 2005). The major fatty acids predominant in palm oil are oleic and palmitic acids (Salunkhe et al., 1992). Fatty acids play a very important role in fats and oils because of their health implications in the human diet and properties in industrial processes. The type of fatty acid determines the nutritional status and storability (keeping quality) of the oil.

2.2 Factors affecting the quality of CPO

Palmitic acid increases in palm oil are mostly associated with oils produced from over-ripe, bruised and crushed fruits, fruits subjected to severe impacts from loading and off-loading bunches and oils stored over long periods (Salunkhe et al., 1992; Tagoe, 2008). Autocatalytic hydrolysis of the oil in the presence of moisture also increases the fatty acid content (Purseglove, 1975). Free fatty acids in oils and fats may also be caused by the action of microbial lipases (Odunfa, 1989).

Microorganisms are known to cause chemical changes in palm oil that lead to deterioration in the (Okpokwasili and Molokwu, 1996). The lipolytic activity of fungi on the triglycerides of oils and fats used in baking formulations may cause rancidity, acidity, bitterness, soapiness and other off flavours. Such activities may occur in seeds or other plant parts from which oils are derived (Larry, 1987).

Fermentation occurs while allowing the fruit to stand for one or more days after harvest prior to processing to initiate loosen out of bunches. Ituen and Modo (2000) revealed that the numbers of days the fruits are allowed to ferment has an effect on the quantity and quality of the oil produced. Fermentation may ensure food safety, extend the shelf-life, improve digestibility and reduce anti-nutritive factors (Nout et al., 1989). Cooke et al., (1987) revealed that fermentation improves the nutritional properties of food products. Palm fruits are sometimes processed mechanically without fermentation, but with the extraction is less efficient.

2.2.1 Effect of storage period of FFB

One hundred tons of newly harvested FFB were collected and separated into two groups of 50 tons each at the loading ramp platform inside the factory which they used to collect the sample (Jimoh and Olukunle, 2011). The experiment was carried out under close monitoring from the day of harvest, (i.e., zero day of fermentation) and for every other day for ten consecutive days of fermentation. Production parameters such as extraction rate, free fatty acid, moisture content, dirt content and oil grade were determined. Oil with FFA 5% is called Special Palm Oil (SPO), while the one with FFA>5% is called Technical Palm Oil (TPO). Special Palm Oil is the best grade and is acceptable in the international market, while TPO can be sold locally ((Jimoh and Olukunle, 2011).

The correct timing of fermentation of fresh fruit bunches has shown to improve the quality and quantity of the palm oil produced. The internationally accepted quality standard oil is produced up to 5th day of fermentation for the wetted sample and 6th day of fermentation for the un-wetted sample. Beyond these days, a gradual deterioration of FFB, as a result of microbial reaction, would have changed the oil from SPO grade to TPO grade. The TPO grade is of poor quality, and the economic value of the oil is reduced. It is recommended that fresh fruit bunches be processed within the first five days of fermentation during the rainy season, while up to six days of fermentation is allowed during the dry season for effective marketability (Jimoh and Olukunle, 2011).

In the study of Tagoe et al (2012) freshly harvested palm fruit bunches from the field were immediately chopped (cut) with an axe after harvesting. The fruits were picked from the spikelet and 0.5 tons loose fruits were stored in an open pile of 63.0 cm for 0, 3, 6, 9, 12, 19 and 26 days before processing. The quality of palm oil is greatly influenced by the method of processing. The scale of operations differs at the level of processing and this affects the quality of the final product. The work shows that the free fatty acid content of palm oil is determined by two factors. The first and major factor is the length of storage of the fruits used to process the oil. The second factor is the length of storage of the oil after processing. Oils processed from the fresh fruits have a very low initial FFA (0.45%) content compared with those from 6 (6.02%), 12 (11.34%) and 26 (32.37%) day old fruits. Results also show that the high grade oils, those with very low FFA content, contain microbes and the longer the oil is stored, the higher the microbial load (Tagoe et al., 2012).

The only persistent organism in oil from the fresh fruits is Hirsutella spp. Occurrence of fungal species in oil from the 12-day storage fruits was highly variable. Peak area ratio for the fungal spp increased with increase in storage period, the longer the storage period the higher the fungal population. Hirsutella spp. appears to be prominent in oils from fresh, 12 and 26 days fruits due to its higher peak area ratio and population. The peak area ratio for Hirsutella is 3.02 compared to 1.94 and 1.93 for Candida and Geotrichum respectively. For the bacteria spp, peak area ratio of Leuconostoc and Waddlia spp. were variable. Pseudomonas maintained high peaks in zero and 6 days fruits compared with the very low peaks in 12 and 26 days fruits and. Generally, the population of all the organisms increased in storage. Lactococcus maintained high peaks in 6, 12 and 26 days. The length of storage of the oil samples were positively correlated (r = 0.929) with the bacterial load. Palm oil stored for 12 months had the largest bacterial load of 2.18, followed by those stored for 6 (1.59) and 0 months (1.17) (Tagoe et al.,, 2011).

2.2.1.1 Effect of storage period of FFB on FFA contents in CPO

In the study of Jimoh and Olukunle (2011) the FFA for the wetted sample increases on a daily basis from 0.10% on zero day to 14.00% on 10th day, but with 5.00% on 5th day of fermentation; while the un-wetted sample also increases on a daily basis from 0.10% on zero day to 10.60% on 10th day, but with 4.32% on 6th day of fermentation. The reason for the continuous increase in the FFA level especially after the first two days of fermentation is as a result of the microbial decomposition of the black outer pigment of the fruits. For the wetted sample, the microbial oxidation of the readily-degradable organisms is high because of its high biological oxygen demand (Jimoh and Olukunle, 2011).

The longer the fruits were stored, the higher the contamination and deterioration and the higher the free fatty acid content of the oil (Tagoe et al., 2012). Length of storage of fruits before processing into oil were positively correlated (r = 0.972) with the FFA. FFA of oil processed from the fresh fruits did not change significantly even when stored for twelve months and still remained within the acceptable standard level of 5%. However, the deterioration (FFA) of all the oils from fruits stored for different periods were above the standard level of 5%. It is observed that the longer the fruits and oil are stored, the higher the FFA and therefore the higher the deterioration (Tagoe et al., 2012).

Even though FFA content of palm oil processed from the fresh fruits and the large scale mill remained within the standard level of 5%, it is obvious from the microbial analysis that the high-grade oils which have low FFA contain microbes. The longer the oil is stored, the higher the microbial load. Work done by Odunfa (1989) on the deterioration of Nigerian palm oil in storage showed that microbial attack leads to hydrolysis of the oil and hence the formation of free fatty acids. The FFA content of palm oil was determined by the storage period (days after harvesting) of the fruits before processing into oil and the storage period of the oil after processing. Fruits that have been stored for long periods prior to processing have high FFA contents. Oil processed from six-day old stored fruits however had an initial FFA of 6.02%, whilst 12-day old stored fruits had an initial FFA of 11.34% and 26 days had an initial FFA 0f 32.37%. These initial FFAs are well above the standard accepted level. Results

Obtained confirm reports that oil from over-ripe fruits contain high levels of FFA (Salunkhe et al., 1992).

In some cases, the harvested FFB can be kept at room temperature for one week or more before they are processed. The harmful effect of fermentation is the continuous build up of FFA in the mesocarp of the fruit under the action of the lipase. Once the fruits are processed, the lipase is no more active (Frank et al., 2011). The high FFA level reported in this study of Amanda et al (2013) could be associated with the postharvest handling practices employed during processing of oil palm such as period of fermentation (Ohimain et al., 2012a). Ohimain and Izah (2013b) have reported a fermentation period of 2 – 3 days after bunch reception in a semi mechanized palm oil mill.

2.2.1.2 Effect of storage period of FFB on moisture contents (MC) in CPO

In the study of Jimoh and Olukunle (2011) the MC for the wetted sample increases on a daily basis from 0.12% on zero day to 1.48% on 10th day, but with 0.30% on 5th day of fermentation; while the un-wetted sample also increases on a daily basis from 0.12% on zero day to 0.72% on 10th day, but with 0.24% on 6th day of fermentation. As the days of fermentation progress, the readily degradable particles dissolve in the oil during processing to raise both moisture and dirt content in gradual formation of sludge (Jimoh and Olukunle, 2011).

Temperature within the fruits increased with the age of fruits and decreased with size of the pile. Moisture content of the fruits however, decreased with age, while contamination and deterioration of the fruits increased with age (Tagoe et al., 2012). But Tagoe and others (2012) have said that the length of storage of fruits (0, 3, 6, 9, 12, 19, 26 days) before processing into oil did not have any influence on the moisture and impurity content of the oil because differences observed in the fruit types were not significant. Moisture and content of oils examined was above the standard levels of 0.01-0.04 and 0.1% for moisture.

2.2.2 Effect of fruit damage on quality of CPO

Fatty acids are generally present in oils as part of triacylglycerol molecules. The presence of free fatty acids moieties in palm oil is an indication of the impairment of oil quality. This process is essentially attributed to an active lipase present in the mesocarp of the oil palm fruit and which is responsible for the hydrolysis of triacylglycerols (Henderson and Osborne, 1991; Sambanthamurthi et al., 1995; Ngando et al., 2006). The lipase is activated at maturity upon bruising and/or wounding of the fruit. According to Desassis (1957), 15 min are enough to hydrolyze 40% of the triacylglycerols of a bruised ripe fruit. However, this endogenous lipase activity was found to be very variable, and some lines with very low lipase activity were identified. The crude palm oil extracted from the fruits of these low lipase activity lines also showed a low FFA/oil acidity content (Ngando et al., 2008).

FFA can also be generated to some extent by contaminating lipases from microorganisms (Hiol et al., 1999; Houria et al., 2002). In order to limit lipase activity, fresh fruit bunches must be handled gently and above all, processed rapidly after harvest. The quality of CPO is influenced by deterioration due to microbial infestation that occurs in the palm fruit via bruises that may have occur before processing (Chabiri et al., 2009).

Hartley (1988) reported that bruising of ripe oil palm fruits could increase the FFA because it contains auto-lipolytic enzymes which split the fruit oil to fatty acid and glycerol.

2.2.3 Effect of transportation of FFB on quality of CPO

Okechalu et al (2011) reported that the exposure of palm fruit to sunlight prior to fermentation also enhances the FFA content of the CPO produced from it.

2.3 Methods of quality evaluation of CPO

2.3.1 Testing FFA content

Tagoe et al (2012), Jimoh and Olukunle (2011) and Nualwijit (2014) tested FFA a content of palm oil by titration and this the most popular method. Pre-heated oil (heated to about 50°C) mixed with aliquots of ethanol (50 ml) and the mixture was titrated with NaOH using phenolphthalein indicator. The volume (V) of NaOH required to produce the first permanent pink colour was recorded and the free fatty acid content of the oil was determined from the formula (Tagoe et al ., 2012).

The other way of determining FFA content was mentioned here. Fatty acids were transformed to their methyl esters following the method of Institute Adolfo Lutz (2005) and were determined with a Shimadzu, Model 17A gas chromatograph (Shimadzu, Japan) equipped with a flame ionization detector (FID), split/splitless injector, and CP-Sil 88 capillary column (100 m × 0.25 i.d., 0.25 μm film thickness) (CP 7420 Varian, EUA). The operation parameters were as follows: column temperature held at 45 °C for 2 min, then increased at 20 °C min1 to 165 °C and held at this temperature for 15 min, and then increased at 4 °C min1 until 220 °C (35 min). The injector and detector were kept at 250 °C. The gas flow rates used were 1 mL min1 carrier gas (He), 30 mL min1 for H2 and 300 mL min1 for synthetic air. The sample split mode was 1/40. The injections were performed in duplicate, and the double injection volume was 1 μL. For the fatty acid identification, the retention times were compared to those of standard methyl esters (Sigma, St. Louis, MO, USA). For quantification (in g fatty acid 100 g1 of total lipids), tricosanoic acid methyl ester from Sigma (USA) was used as an internal standard (23:0) at 2.5 mg mL1 in n-hexane. Theoretical FID correction factor (Visentainer and Franco, 2012) values were used to obtain the concentration values. Fatty acid contents were reported in g per 100 g of total lipids.

2.3.2 Testing of moisture content

Tagoe and others (2012) used McCartney bottles were washed with water and oven dried for 30 minutes. Two gram of oil was added and the samples were dried at 105˚C for 4 hr and cooled in a desicator and re-weighed. They replicated all the samples three times. Moisture content of the oils was determined by the formula.

Jimoh and Olukunle (2011) determined the MC using the below procedure.Ten grams of oil sample was poured into a crucible and place inside oven for 90 minutes. Then it was cooled inside desicator for 60 minutes.

2.3.3 Testing impurities content

Tagoe et al (2012) tested impurities content of palm oil using below procedure. Gooch crucibles were lined with filter paper, washed with hexane, and dried at 105˚C for 30 minutes. The crucibles were allowed to cool and weighed. Two gram of oil added the hexane (20 ml) was added to the oils and the flasks swirled and heated to homogenize the mixtures. The mixtures were poured into the crucibles and allowed to drain. The flasks were rinsed with hexane and poured into the crucibles. This was done to remove any particles present in the flasks. The crucibles were removed after all the solutions had drained and dried at 105˚C for 30 minutes. They were cooled and reweighed (W4). Impurity in the oil was expressed as a percentage from the formula.

Jimoh and Olukunle (2011) determined the impurities content of palm oil using below procedure. Oil sample was poured into clean and sterilized calibrated test tube. It was mounted into the centrifugal machine. Then impurities content were calculated using a formula.

.

2.3.4 Peroxide Value determination

The peroxide value was determined by titrating chloroform/glacial acetic acid/potassium iodide solution of the oil with an aqueous solution of sodium thiosulphate using starch as indicator (Aletor et al., 1990). About 5g of oil was weighed into the 250ml conical flask. A mixture of glacial acetic acid and trichloromethane chloroform (30ml) was added in a ratio of 3: 2. About 0.5ml of saturated potassium iodide solution was also added. The mixture was properly shaken. 30ml of water was added. The solution was filtrated with 0.01M sodium thiosulphate, while slowly adding the titrant with a continuous shaking until a yellow colour is shown. About 5ml of starch indicator was added to the titration process while shaking vigorously until a blue-black colour is discharged. A blank sample devoid of CPO was also analyzed using the same procedure. The peroxide value has been expressed mathematically.

CHAPTER III

3. MATERIALS AND METHODS

3.1 Location

The research was conducted at AEN Palm Oil Processing (Pvt) Ltd, Maragahadeniya, Baduraliya, Sri Lanka and samples were taken from the receiving point of the factory.

3.2 samples

3.2.1 Sample collection – experiment I

FFBs of oil palm which were in ripen stage were randomly selected from the receiving point of the factory and made sure to select bunches without fruit damage. Similarly, FFB which are in ripen stage were selected by visiting the estate and they were handled carefully while transportation. Transportation was done soon after harvesting without exposing sunlight or rain. FFB for both samples were harvested at the same time to avoid variations.

3.2.2 Sample collection – experiment II

FFBs of oil palm which were in ripen stage were randomly selected from the receiving point of the factory and fruits in different damage levels were selected and damage levels which were selected were 0%, 20%, 40% and 60% of the fruit surface. All the samples were taken from e same estate. Harvesting details of the FFB were taken by questioning the workers.

3.3 Experiment design

3.3.1 Experiment I

All the samples were stored in an ambient condition and CPO extraction was done six by six hours up to 60 hours. Four replicates were used and experiment was design two factor factorial complete randomized design (CRD).

3.3.2 Experiment II

All the samples were stored in an ambient condition and CPO extraction was done six by six hours up to 24 hours. Four replicates were used and experiment was design two factor factorial complete randomized design (CRD).

To find out the maximum storage period of FFB, FFA and moisture content were tested until they went over the standard level of 5% of the FFA and 0.3 % of the moisture. Experiment was continued until the CPO went over the standard level and it was stopped after meeting one of above quality parameter.

3.4 Oil extraction

Samples were stored in ambient condition and four replicate were selected. Fruits were detached from bunches and cleaned using a tissue paper. Then they were weighted into a clean beaker (250 ml) and water was added until fruits were covered. The beaker with fruits and water were kept on hotplate and cooked for 4 hours. After that water was removed from the beaker and fruits with beaker were kept in a desicator until they cooled. The nuts of the fruits were separated using spatula. Mincing and chopping was done using mortar and pestle. Petroliam ether (PE) was added into the chopped mesocarp of the oil palm. Oil with PE were filtered using whatman filter paper and filtrate were evaporated at 80 0C. Glass rod was used to check weather evaporation of oil was enough and glass rod was put into the beaker but above the oil level and until the liquid PE was not on the glass rod evaporation was done. Then extracted CPO was kept in a desiccators for 10 min for cooling.

This procedure was followed for each and every replicates, each sample in different storage period and for both experiment.

Figure 1 Research method

3.5 Testing FFA contents in CPO

Five gram of CPO was weighted into clean conical flask (250 ml) and pre heating was done at 50 oC for few minutes. Then 50ml of neutralized IPA was added in to the flask and few drops of PP were added into the mixture. Then it was titrated with 0.0875N KOH and burette reading was taken. Then the FFA % was calculated using the formula and it was the palmatic acid content.

FFA% = 25.6 g mol-1* 0.0875 mol ml-1* V ml / 5 g

 

Figure 2 Testing FFA content in CPO

 

3.6 Testing moisture contents in CPO

Figure 3 Testing moisture content of CPO

A metal plate which did not have moisture was weighted (W1) and 10 g of CPO was added into it. Then it was labeled and kept in the over at 103.5 oC for 2.5 hours. After that metal plate was kept in desiccators for cooling. Then it was weighted and drying until it got a constant weight (W2). Then the moisture percentage was calculated wet basis and following formula was used.

Moisture% = (W2– W1 g) / (10 g)* 100

 

3.7 Data analysis

Two factor factorial CRD was used to analyze the data in both experiments and ANOVA of the experiment was prepare to find out the significant effect of the postharvest handling operations on quality of CPO at the significant level of 0.05 (p=0.05). Regression analysis was done to find the relationship between the postharvest handling operations on quality of CPO. Average of the replicates was taken to draw the graphs. Line charts were used to find out the maximum recommended days for post harvest storage of FFB.

 

CHAPTER IV

4. RESULTS AND DISCUSSION

4. 1 Sample selection for the experiments

The entire samples were selected from the same estate to minimize the variation among samples. Quality of the CPO is affected by climatic condition, soil and to minimize those effects, only above estate was selected. Zero level damaged fruits were selected for the experiment one which is to fine out the effect of transportation and storage period on FFA and moisture contents. if the fruit is damaged, lipase enzymes come out from the ruptured cells. They may react with glycerides and FFA may be produced (Hartley 1988). All the samples were harvested at the same time for the experiment one and samples for the experiment two has also been selected by minimizing the errors.

4.2 Effect of storage period and transportation of FFB on quality of CPO

4.2.1 Effect of storage period and transportation of FFB on FFA contents in CPO

According to the statistical analysis there is a significant effect of FFB transportation on FFA content of CPO (p<0.05). To analyze that samples which were in two transportation conditions were selected. All the time FFA percentage of CPO extracted from the FFB which were at the receiving point are higher than the FFB which were taken by visiting the estate. Only the difference for the sample was the transportation mode and FFB taken by visiting the estate were covered well soon after harvesting and was not exposed to sunlight and there were no effect of gases like ethylene which were emitted by the fruits. Okechalu et al (2011) reported that the exposure of palm fruit to sunlight prior to fermentation also enhances the FFA content of the CPO produced from it.

CPO were extracted from the FFB stored in different periods were titrated with NAOH and FFA% was calculated. FFA% Of CPO from FFB of the receiving point were significantly different (p< 0.05) from the FFB by visiting the estate. Average FFA% of CPO from receiving point was 0.36% ± 0.02 and Oil was extracted after storing 6 hrs. It was 5.39%±0.05 for 60 hrs of storage period. And also the FFA % of the CPO which was extracted from the FFB taken by visiting the estate was lower than the previous one. It was 0.33%± 0.01 for store period of 6 hrs and 5.34%± 0.07 for 60 hrs.

Table 1 FFA % of CPO from FFB stored for different storage period

Storage period of FFBFFA% of CPO from FFB
Taken from the receiving pointTaken by visiting estate
6 h0.33± 0.010.35±0.01
12 h0.46±0.010.50±0.01
18 h0.64±0.010.68±0.01
24 h0.78±0.020.81±0.02
30 h1.41±0.021.43±0.02
36 h1.94±0.011.95±0.02
42 h2.91±0.052.94±0.04
48 h3.89±0.033.91±0.02
54 h4.68±0.014.70±0.03
60 h5.34±0.075.39±0.05

With the storage period FFA % CPO of was increased in both cases. The longer the fruits were stored, the higher the contamination and deterioration and the higher the free fatty acid content of the oil (Tagoe and others 2012). It is observed that the longer the fruits and oil are stored, the higher the FFA and therefore the higher the deterioration (Tagoe and others 2012).

Figure 4 Relationship between FFA% in CPO and FFB transportation

 

Figure 5 FFA% of CPO extracted from FFB stored for different period

FFA content in CPO was increased with the storage period of FFB and it was significant (p<0.05) both samples. And also the storage length of FFB which was taken from the receiving point before processing was positively correlated (r = 0.993) with the FFA% of CPO. The relationship between the FFA % and storage period was exponential and it was a strong relationship (R2= 0.9852). FFA % of CPO extracted from the FFB which taken by visiting the estate was positively correlated (r= 0.993) with the storage period before they processed and it was also exponential. The relationship between FFA% and storage period was strong (R2= 0.9862).

FFA% of CPO increased with the storage period and it is exponential. According to the industrial quality standard FFA% should be below 5% and it is the palmatic acid percentage (SLS 720:2010). Using the equation of the exponential graph, maximum recommended storage period were calculated for both samples which were transported differently. Considering “ y’’ equals to 5% storage period were calculated.

Figure 6 FFA % of CPO from FFB which were taken from the receiving point and stored for different period

According to the analysis there was no significant interaction effect (p> 0.05) of both storage period and transportation mode on FFA% of CPO.

Oil with FFA 5% is called Special Palm Oil (SPO), while the one with FFA>5% is called Technical Palm Oil (TPO). Special Palm Oil is the best grade and is acceptable in the international market, while TPO can be sold locally ((Jimoh and Olukunle, 2011).

Figure 7 FFA % of CPO from FFB which were by visiting the estate and stored for different period

4.2.2 Effect of storage period and transportation of FFB on moisture contents in CPO

According to the statistical analysis there is no significant effect of FFB transportation on moisture content of CPO (p>0.05). To analyze that samples which were in two transportation conditions were selected. Moisture contents of CPO have not been affected by the transportation. If the FFB got wet, moisture content can be increased. Otherwise while transporting it does not happen.

CPO were extracted from the FFB stored in different periods were used to analyze the moisture and it was done by the oven dry method. Moisture contents were calculated using the standard formula. The moisture % Of CPO from FFB of the receiving point were not significantly different (p> 0.05) from the FFB by visiting the estate. Average moisture % of CPO from receiving point was 0.13% ± 0.01 and Oil was extracted after storing 6 hrs. It was 0.33%±0.01 for 60 hrs of storage period. And also the moisture % of the CPO which was extracted from the FFB taken by visiting the estate was 0.13%± 0.00 for store period of 6 hrs and 0.33%± 0.00 for 60 hrs.

Table 2 moisture % CPO from FFB stored for different storage period

Storage period of FFBMoisture % of CPO from FFB
Taken from the receiving pointTaken by visiting estate
6 h0.12± 0.010.13±0.00
12 h0.14±0.010.14±0.01
18 h0.15±0.000.15±0.00
24 h0.18±0.000.18±0.01
30 h0.19±0.000.19±0.00
36 h0.21±0.000.20±0.00
42 h0.22±0.010.22±0.01
48 h0.25±0.010.25±0.00
54 h0.32±0.000.32±0.00
60 h0.33±0.000.33±0.00

With the storage period moisture % of was increased in both cases. Moisture content in CPO was increased with the storage period of FFB and it was significant (p<0.05) both samples. As the days of fermentation progress, the readily degradable particles dissolve in the oil during processing to raise both moisture and dirt content in gradual formation of sludge (Jimoh and Olukunle 2011). And also the storage length of FFB which was taken from the receiving point before processing was positively correlated (r = 0.9709) with the moisture% of CPO. The relationship between the moisture % and storage period was exponential and it was a strong relationship (R2= 0.9427). Moisture % of CPO extracted from the FFB which taken by visiting the estate was positively correlated (r= 0.9708) with the storage period before they processed and it was also exponential. The relationship between moisture % and storage period was strong (R2= 0.9425).

Figure 8Relationship between moisture% in CPO and FFB transportation

Figure 9 Moisture % of CPO extracted from FFB stored for different period

Figure 10 Moisture % of CPO from FFB which were taken from the receiving point and stored for different period

Figure 11 Moisture % of CPO from FFB which were taken by visiting the estate and stored for different time period

According to the analysis there was no significant interaction effect (p> 0.05) of both storage period and transportation mode on moisture% of CPO.

4.3 Effect of storage period and damage percentage of FFB on quality of CPO

4.3.1 Effect of storage period and damage percentage of FFB on FFA contents in CPO

According to the statistical analysis there is a significant effect of damage percentage on FFA content of CPO (p<0.05). To analyze that samples which were in four damage level (0%, 20%, 40%, 60%) were selected. All the time FFA percentage of CPO extracted from the FFB which were damaged by 60% are higher than the FFB which were damaged by 40%. Likewise FFA% was increased with the damage level. Only the difference for the samples was the damage percentage of the fruit surface. All the samples were taken from the receiving point and all were from the same estate. And also all were harvested at the same time and all were transported by a same lorry. The lipase is activated at maturity upon bruising and/or wounding of the fruit. According to Desassis (1957), 15 min are enough to hydrolyze 40% of the triacylglycerols of a bruised ripe fruit. Hartley (1988) reported that bruising of ripe oil palm fruits could increase the FFA because it contains auto-lipolytic enzymes which split the fruit oil to fatty acid and glycerol.

CPO were extracted from the FFB stored in different periods were titrated with NAOH and FFA% was calculated. FFA% Of CPO from FFB of which was in different damage level were significantly different (p< 0.05) from the other. Average FFA% of CPO at 0%, 20%, 40% and 60% fruit damage was consecutively 0.37% ± 0.01, 1.44±0.02, 2.72±0.03 and 3.93±0.02 as well Oil extraction was done after storing 6 hrs. It was consecutively 0.78±0.01, 3.25±0.02, 5.16±0.02 and 6.80±0.01 for 24 h hrs of storage period. FFB which were in 4 different damaged levels were used to test FFA % until they went over the standard level of 5% (SLS 720:2010). The FFA% of CPO which were extracted from FFB at 0%, 20%, 40% and 60% damage level went over the standard level consecutively the storage period of 60 h, 42 h, 24 h and 12 h. it shows that higher the level of fruit damage have lower the storage period to reach the standard level of FFA%.

Figure 12 Relationship between FFA% in CPO and fruit damage

Figure 13 Relationship between FFA% in CPO and fruit damage and the correlation

FFA% of CPO was positively correlated (r> 0.9) with the damage percentage of fruits and there was strong relationship (R2> 0.9) between FFA% and the damage percentage of fruits.

With the storage period FFA % CPO of was increased in every samples. The longer the fruits were stored, the higher the contamination and deterioration and the higher the free fatty acid content of the oil (Tagoe and others 2012). It is observed that the longer the fruits and oil are stored, the higher the FFA and therefore the higher the deterioration (Tagoe and others 2012).

Table 3 FFA % of CPO from FFB stored for different storage period

Storage period of FFBFFA% of CPO from FFB in different level of damage
0% 20% 40% 60%
6 h0.37± 0.011.44±0.022.72±0.033.93±0.02
12 h0.5±0.012.11±0.023.58±0.025.46±0.01
18 h0.68±0.012.47±0.064.37±0.036.01±0.01
24 h0.80±0.013.25±0.025.16±0.026.80±0.01
30 h1.44±0.023.58±0.025.79±0.01N/A
36 h1.96±0.044.37±0.03N/AN/A
42 h2.94±0.075.20±0.05N/AN/A
48 h3.91±0.025.73±0.02N/AN/A
54 h4.70±0.036.51±0.02N/AN/A
60 h5.39±0.06N/AN/AN/A
66 h6.21±0.02N/AN/AN/A

FFA content in CPO was increased with the storage period of FFB which were in 4 different damage levels and it was significant (p<0.05) both samples. And also the storage length of FFB which were in 4 different damage levels before processing was positively correlated (r > 0.9) with the FFA% of CPO. The relationship between the FFA % and storage period was exponential and it was a strong relationship (R2> 0.9).

Table 2 Maximum recommended storage period for FFB which were damaged in different level of percentages and the regression data

Damage percentage of the fruitR2lrlExponential equationStandard value of FFA% (y)Maximum recommended storage period (h)
0%0.97840.989y = 0.2868e0.0504x5%57
20%0.97210.986y = 1.4096e0.0301x5%42
40%0.97480.987y = 2.3814e0.0313x5%23
60%0.91230.955y = 3.522e0.0291x5%12

According to the two factors factorial CRD analysis, there is a significant effect (P< 0.05) of damage percentage of FFB on FFA% of CPO. In the calculation, it was clearly shown ( Table 3). Fruits which were in 0% damage can be stored for 57 hours.

According to the analysis there was a significant interaction effect (p<0.05) of both storage period and transportation mode on FFA% of CPO.

4.3.2 Effect of storage period and transportation of FFB on moisture contents in CPO

According to the statistical analysis there is a significant effect of damage percentage on moisture content of CPO (p<0.05). To analyze that samples which were in four damage level (0%, 20%, 40%, 60%) were selected. All the time moisture percentage of CPO extracted from the FFB which were damaged by 60% are lower than the FFB which were damaged by 40%. Likewise moisture% was decreased with the damage level. Only the difference for the samples was the damage percentage of the fruit surface. All the samples were taken from the receiving point and all were from the same estate. And also all were harvested at the same time and all were transported by a same lorry.

CPO were extracted from the FFB stored in different periods were used to analyze the moisture %. Moisture % Of CPO from FFB of which was in different damage level was significantly different (p< 0.05) from the other. Average moisture% of CPO at 0%, 20%, 40% and 60% fruit damage was consecutively 0.13% ± 0.01, 0.12±0.00, 0.11±0.00 and 0.10±0.68 as well Oil extraction was done after storing 6 hrs. It was consecutively 0.18±0.00, 0.15±0.00, 0.14±0.00 and 0.13±0.87 for 24 h hrs of storage period. FFB which were in 4 different damaged levels were used to test FFA % until they went over the standard level of 5% (SLS 720:2010). The FFA% of CPO which were extracted from FFB at 0%, 20%, 40% and 60% damage level went over the standard level consecutively the storage period of 60 h, 42 h, 24 h and 12 h and moisture percentages of that time periods were below the standard level of 0.3% except fruits which were damaged 0%. it shows that higher the level of fruit damage have higher the storage period to reach the standard level of moisture%. But first meeting standard either moisture% or FFA% were considered to decide the maximum recommended storage period.

Figure 14 Relationship between moisture % and fruit damage

Even though moisture % increased with the time, it negatively correlated (lrl. 0.9) with the damage percentage of the fruit and there was a strong relationship (R2> 0.9) between the level of fruit damage and the moisture content.

Table 3 Relationship between moisture % and fruit damage with the storage period

Storage periodlrl
6 hR² = 0.9769lrl =0.988
12 hR² = 0.9783lrl =0.989
18hR² = 0.9771lrl=0.988

Table 4 Moisture % of CPO from FFB stored for different storage period

Storage period of FFBMoisture % of CPO from FFB with different level of fruit damage
0%20%40%60%
6 h0.13± 0.010.12±0.000.11±0.000.10±0.67
12 h0.14±0.010.13±0.000.12±0.000.11±0.74
18 h0.15±0.000.14±0.000.13±0.000.12±0.81
24 h0.18±0.000.15±0.000.14±0.000.13±0.87
30 h0.19±0.000.17±0.000.16±0.00N/A
36 h0.20±0.000.19±0.00N/AN/A
42 h0.22±0.010.20±0.01N/AN/A
48 h0.25±0.000.21±0.00N/AN/A
54 h0.29±0.000.23±0.00N/AN/A
60 h0.33±0.01N/AN/AN/A
66 h0.35±0.00N/AN/AN/A

With the storage period FFA % CPO of was increased in every samples. As the days of fermentation progress, the readily degradable particles dissolve in the oil during processing to raise both moisture and dirt content in gradual formation of sludge (Jimoh and Olukunle, 2011).

The Moisture content in CPO was increased with the storage period of FFB which were in 4 different damage levels and it was significant (p<0.05) both samples. And also the storage length of FFB which were in 4 different damage levels before processing was positively correlated (r > 0.9) with the moisture of CPO. The relationship between the moisture % and storage period was lenior and it was a strong relationship (R2> 0.9).

Figure 15 Relationship between moisture and storage period with fruit damage

According to the analysis there was a significant interaction effect (p< 0.05) of both storage period and fruit

CHAPTER V

5. CONCLUSION AND RECOMMENDATION

FFA% of CPO is affected by the transportation mode. It is due to the excessive handling, sunlight, wetting or exposing to gases like ethylene and storage period is increased the FFA % of CPO. It is further facilitated by the microorganisms on the fruit surface. But there is no interaction effect of transportation mode and storage period of FFB before processing. Damage percentage of fruits increase the FFA% of CPO and it is due to the cell rupturing as well as lipolytic reaction. It is accelerated by the lipolytic microorganisms. There is an interaction effect of storage period and fruit damage level of FFA% of CPO.

Moisture% of CPO is not affected by the transportation mode. It can be affacted due to, wetting only and storage period is increased the moisture % of CPO. It is further facilitated by the microbial decompositions of fruit. But there is no interaction effect of transportation mode and storage period of FFB before processing. Damage percentage of fruits decrease the moisture% of CPO and further studies needed. There is an interaction effect of storage period and fruit damage level of moisture% of CPO.

According to the fruit damage level maximum recommended storage period are different. It is recommended to store FFB 57 h, 42h, 23 h and 12h for the fruit damage level of 0%, 20%, 40%, 60%.

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