Production and properties of fractionated products of red palm oil and applications as functional ingredients in pad Thai sauce, chocolate, and Nile tilapia fish (Oreochromis Niloticus) feed

Abstract

This research aimed to develop the red palm oil and red palm fats production technique, which is simple and economical for Thai SMEs. The crude palm oil was acid degumming with the ninefold diluted of 0.06% (w/w) phosphoric acid and 0.04% (w/w) citric acid and degummed at 90 ˚C for 20 min with vigorous agitation. The sedimented gum was separated from the oil by washing the acid oil with warm water at 60 ˚C. The excess of free fatty acids and phosphorus content were removed by NaOH and carried out in 80 ˚C temperature for 30 min with constant stirring. Soap from the saponification reaction and excess NaOH were washed out with warm water at about 60 ˚C. After neutralization, the oil contained 0.46±0.05% fatty acids, 637.60±8.64 mg/kg carotenoids, 74.48±9.39% crude palm oil yield, 0.15±0.05 mg/kg iron, and 0.59±0.00 mg/kg copper, and the phosphorus content was not detected. The degumming and neutralization were followed by the multi-step fractionation using crude palm oils which prepared by steam and vacuum frying sterilizations. The optimal condition of vacuum frying sterilization was 80 ˚C under vacuum at -50 to -72 cm.Hg. The palm fruits were fried until the water content is less than 7%. After neutralization, the oil contained 0.47±0.07% fatty acids, 533.98±12.76 mg/kg carotenoids, 74.77±3.43% crude palm oil yield, < 0.1 mg/kg iron and copper, and the phosphorus content was not detected. The crystalized temperatures of the steam crude palm oil were at 34 ˚C, 25 ˚C and 15 ˚C, whereas those of the vacuum fried CPO were 34 ˚C, 27 ˚C and 17 ˚C. Using the slow cooling rate of 0.17 ˚C/min produced the red palm oil with higher yield and higher carotenoids content than those using the fast cooling rate of 1.00 ˚C/min. The red palm oil, which prepared by the steam sterilization, was evaluated for the anti-inflammatory activity. The results showed that the oil could decrease the LPS-induced expression, and decrease the activities of inflammatory mediators and pro-inflammatory cytokines by suppressing the NF-κB and MAPK signaling pathways in RAW264.7 macrophages cell. This study suggested that the prepared red palm oil has anti-inflammatory activities and has potential as an anti-inflammatory faction. Development of Pad Thai sauce from red palm oil prepared by the steam sterilized crude oil was carried out by studying the main product characteristics using the ideal ratio profile test. The most suitable Pad Thai sauce recipe from red palm oil comprised of 40.70 g sugar, 4.15 g black soy sauce, 35 g tamarind juice, 20 g shallot, 15 g garlic, 12 g fish sauce, 8 g vinegar, 1.5 g salt, 0.5 g chili powder and 14 g red palm oil. The 80 g Pad Thai sauce provided 37 g carbohydrate, 2 g protein, 8 g fat, 3 g fiber, 35 g sugar, 230 kcal of energy and no cholesterol. The sauce had DPPH and FRAP antioxidant values at 1.90±0.04 μmol TE / g and 4.59±0.36 mmol TE / g, respectively. The shelf life of the Pad Thai sauce, packed in a laminated bag and kept at 25 ˚C, was 1 year and 30 days. Red palm fat could be used as a substitute ingredient in chocolate and animal feed production. Red palm fat prepared by the steam sterilized crude oil and obtained from crystallization at 34 ˚C can be used to replace up to 60% of the commercial cocoa butter in producing chocolate. Quality of the chocolate produced from 60% cocoa substitute complied with the product standard. The shelf life of the chocolate at 30 °C was 4 weeks. The red palm fat obtaining from crystallization at 25 ˚C was used to replace soybean oil in the Nile Tilapia feeds for the fish under 13 weeks old. The selected red palm fat could be totally replaced all soybean oil used in the feed formulas. The physical, chemical, and microbiological properties of the developed feeds were agreed with those suggested in the report, and the floating rates of the developed feeds were higher than those of the commercial feeds.