Study of Crude Palm Oil (CPO) Handling and Storage Process in Palm Oil Mills in an Effort to Improve CPO Quality and Reduce the Risk of Contaminants Formation

: Crude Palm Oil (CPO) is palm oil obtained from the extraction or compression process of oil palm fruit flesh and has not been purified. Palm oil is usually used for food, cosmetic industry, chemical industry, and animal feed industry. Increasingly open insight and increasing consumer awareness of the importance of food safety and quality assurance supported by technological developments and laboratory analysis methods, new types of contaminants in food products are also found. Currently, the Indonesian government is facing challenges regarding the issue of 3-monochloro-1,2-propanediol ester (3-MCPD Ester) and glycidyl ester (GE) in palm oil which can hamper Indonesia's palm oil trade in the future. The aim of this research to modify the pumping time and storage time of CPO from Reclaimed tank to (Vertical Clarifier Tank) VCT. The study demonstrated that the length of time for pumping CPO from reclaimed tanks to VCT and the length of time for CPO storage up to 20 days had a significant effect on the quality of ALB, PV, DOBI and DF.

Based on the explanation above, it is deemed necessary to conduct research with the aim of evaluating several quality parameters of CPO and their changes related to the risk of formation of 3-MCPD ester and GE contaminants in refinery as well as oxidative stability and color stability of palm oil derivatives in palm oil mills. The length of waiting time for CPO quoted back in the reclaimed tank or pumping time of CPO quoting results into VCT is estimated to affect the quality of mixed CPO and also the oxidative stability of CPO.
This study aims to examine the effect of waiting time or pumping time for CPO from reclaimed tanks to VCT on the quality and stability of CPO during storage. Mixing of CPO from reclaimed tanks and VCT is simulated in the laboratory which is then analyzed for CPO quality parameters which include FFA Content, peroxide value (PV), deterioration of bleachability index (DOBI), and discriminant function (DF) within a certain storage period to look at the oxidative stability of CPO. Based on the CPO quality parameter values mentioned above, the ease of refining CPO in the refinery and the risk of formation of 3-MCPD Ester and GE contaminants can be predicted.

Material
The material used in this study is crude palm oil from the Sawit Seberang palm oil mill, PT. Nusantara II District, Langkat Regency, North Sumatra.

Analysis of the free fatty acid prosedur
Weight 10 g of sample into a 250 ml Erlenmeyer flask, add 25 ml of neutral 95% alcohol and for 10 minutes on a hot plate while stirring, titrate with 2 ml of indicator PP. The mixture is shaken and titrated with 0.1 N NaOH solution until a pink color appears and does not disappear for 30 seconds.
Free Fatty Acid = ml of NaOH × N NaOH × 25.6 massa, g of sample form, can be seen in Figure 1 below. FFA present in oils and fats have been present since the fruit has been harvested, and the amount will continue to increase during processing and storage. CPO quality will decrease if there is contamination by condensate in the sterilization unit, steam and heat injection in the digestion unit, high pressure in the oil oxidation press unit in the clarification unit, and excessive heating in storage [5]. The presence of FFA is usually used as an early indicator of damage to the oil. FFA that appears as a result of further hydrolysis can undergo oxidation reactions [6]. Thus, hydrolysis is a reaction that supports the oxidation reaction of the oil [7] .
During storage and heat treatment, oil will be subject to hydrolysis, oxidation, and polymerization processes which result in a decrease in quality and nutritional value [8]. It is known that there is a heat treatment on the storage of CPO in a tank with a temperature of 45ºC to maintain the viscosity of the CPO so that it is easy to pump further. Thermal oxidation of oil dominates the formation of hydroperoxides known as primary oxidation products which are then degraded into hydrocarbons, aldehydes, and ketones, and subsequently produce secondary oxidation products.
Secondary oxidation products tend to be volatile and give off a rancid taste and odour in the oxidized oil [9]. applied to food products. The oxidative stability of the oil is strongly influenced by the fatty acid composition and the content of minor components naturally present in the related oil. The higher the content of unsaturated fatty acids in the oil, the easier the oil will be damaged [10]. Furthermore, the initial quality condition of natural oil will also greatly affect its oxidative stability.

Day
6.25 ± 0.07 6.4 ± 0.14 6.55 ± 0.07 6.7 ± 0.14 6.8 ± 0.14 20 Day 7 ± 0.14 7.2 ± 0 7.45 ± 0.07 7.7 ± 0.14 7.8 ± 0.14 Note: Data is the average result of 2 replications ± standard deviation From the results of the research, the PV values obtained in table 2, if described in graphical form, can be seen in Figure 2 below. According to Suroso (2013) that the recommended PV value for CPO is a maximum of 6 mek/kg [11]. From this research data, the storage time from 0 days to 12 days and pumping time from 0 hours to 8 hours is still in accordance with the standard. When viewed from the length of storage time >12 days starting from pumping 0 hours to 8 hours, the PV value is already above the standard value.
This indicates that storage time has a higher effect than the pumping time of CPO from reclaimed tanks to VCT, although from table 2 data it can be seen that the PV value continues to increase along with the increase in pumping and storage time. In Figure 2 it can be seen that the pumping time and storage time affect the PV value. This is in accordance with the explanation of Gunawan et al (2003) that heating for a longer time can cause damage to the oil [12]. The heating process accelerates oxidation reactions, decomposition reactions of primary oxidation products, and hydrolysis reactions. An increase in PV levels is an indicator and a warning that soon it will smell rancid [13].
Thus, the stability, shelf life of the oil and the quality of the oil have decreased due to the increase in PV value [14].

The effect of the length of time for pumping CPO from reclaimed tanks to VCT and the effect of storage time on Deterioration of Bleachability Index (DOBI) levels
The results obtained showed a decrease in DOBI in line with an increase in the pumping time of CPO from reclaimed tanks to VCT and an increase in storage time, as can be seen in table 3. can be seen in figure 3 below. A high DOBI value will be obtained if the fruit processed in the palm oil mill is the right ripe fruit, because it contains high levels of carotene. In unripe fruit the DOBI value is low because the carotene content is also low, while in overripe fruit the DOBI value is low because the FFA level is high [15].
Although the DOBI value has not yet become a quality requirement for CPO, several companies have used DOBI for domestic and export trade. Hasibuan., (2012) reported that the average DOBI value in Indonesian CPO was 2.24 with a range of 0.9-2.99 [16]. In this study, the DOBI value at 0 days of storage up to 8 days of storage still met the standard. Refer from the research of quality of indonesian cpo before and some of standart recommended of dobi of cpo in SNI minimum of 2.2 and after a storage time of more than 8 days, the DOBI value of CPO was categorized as lowquality CPO. From table 3 it can be seen that the length of time for pumping CPO from reclaimed tanks to VCT affects the DOBI value during storage, where the DOBI value decreases with each pumping time and storage time. In addition, palm fruit that has been harvested should be processed immediately so that the quality of CPO is high [17].
The factors underlying the low DOBI value in this study were due to contamination of good quality CPO by mixing CPO from reclaimed tanks recovered from sludge palm oil. This practice of CPO recovery is often carried out by several companies in order to obtain high yields to meet targets without paying attention to the impact of the quality of the CPO.  form, it can be seen in Figure 4 below.  should be done <8 days in order to prevent the rate of damage or further degradation of CPO quality.

CONCLUSION
The length of time for pumping CPO from reclaimed tanks to VCT and the length of time for CPO storage of up to 20 days have a significant effect on the quality of FFA, PV, DOBI and DF. The combination of treatment time for pumping CPO from reclaimed tanks to VCT and CPO storage time of up to 20 days has a significant effect on the quality of FFA, PV, DOBI and DF. If the mixing of CPO from VCT and reclaimed tanks must be carried out, pumping should be carried out a maximum of once every 4 hours for storage time, it should only be carried out for up to 8 days before further processing in the refinery.