The Research On DHA Algae Blend Oil Formula Based On The Evaluation Of Cooking And Storage Properties

At present, DHA algae oil, as a new resource, has been widely used in edible blend oil industry. However, DHA loss was not taken into consideration during cooking and storage process when designed the formula of blend oil. In order to design a formula which fitted the Chinese residents’ actual dietary most, DHA algae oil and common vegetable oils were mixed and the cooking and storage stability properties were studied, and also refereed to nutriology basis.Firstly, the soybean oil, peanut oil and canola oil were chosen to be three kinds of base oil for blend oil. Different DHA algae oil contents (2%,3%,5%,10%,15%), two kinds of ingredients (potatoes and chicken) and three cooking ways (steaming, stir-frying and braising) were studied to research the quality changes and DHA loss of blend oil. The results showed: acid values (0.14～1.24 mgKOH/g) were far below the standard requirement(3 mgKOH/g); peroxide values(1.33～4.26 mmol/kg) were also below the standard requirement(0.25 g/100g oil, same as 9.85 mmol/kg); according to the base oil, the order of DHA loss was soybean oil (1.54%～14.20%)<canola oil (3.39%～28.85%)<peanut oil (18.73%～42.68%); sensory assessment showed that peanut oil was the best one as base oil during cooking. The blend samples containing 3% DHA algae oil could satisfy the suggestion recommended intake of DHA (200～300 mg/d)for Chinese residents after cooking. Soybean oil was more suitable to be main base oil of DHA algae blend oil while peanut oil was suitable for improving flavor.Then according to the previous experimental results and the DHA recommended intakes, basic blend oil samples which contained 3% DHA algae oil were prepared. The storage stability of these samples was evaluated with the three methods (oxidation stability tester,39 d accelerated oxidation in 62℃ oven,168 d simulation on family storage (avoid light or not)) respectively. The results oxidation stability were as follows. According to the oxidation induction time, canola blend oil (2.40～4.97 h) was better than soybean blend oil (2.71～3.76 h) and peanut blend oil (1.11～3.91 h). According to the results of accelerated oxidation by oven, acid values showed that soybean blend oil (0.15～0.30 mgKOH/g)<canola blend oil (0.15～0.49 mgKOH/g)<peanut blend oil (0.90～1.22 mgKOH/g), peroxide values showed that canola blend oil (0.66～24.57 mmol/kg)<soybean blend oil(1.92～32.47 mmol/kg)< peanut blend oil(1.90～38.30 mmol/kg) and DHA loss results showed that soybean blend oil (27.26%) <peanut blend oil (28.70%)<canola blend oil (33.53%). As to simulate family storage experiment, the results (acid values, peroxide values and DHA loss) of avoid light storage were better than those of light-storage. The acid values of the two groups were similar and below the standard requirement(3 mgKOH/g) while the peroxide values and DHA loss had big differences. The peroxide values of canola blend oil were below standard (0.25 g/100g oil, same as 9.85 mmol/kg) during the storage process no matter avoid light or not. The peroxide values of soybean blend oil exceeded the standard value at 154d (avoid light storage) and 84d (light-storage) respectively. Peanut blend oil’s peroxide values were over the standard value when avoid light storage for 98d and light-storage for 70d. The DHA loss of avoid light storage showed that soybean blend oil (8.43%)<canola blend oil (10.93%)< peanut blend oil (11.56%), while light storage samples showed that soybean blend oil(14.87%) <peanut blend oil(16.55%)<canola blend oil(19.21%). Comprehensive the above three evaluation methods, the storage stability showed that canola blend oil> soybean blend oil> peanut blend oil and the DHA loss showed that soybean blend oil> canola blend oil> peanut blend oil.Finally, based on the dietary guidelines, actual dietary survey of Chinese residents and the above study results of cooking and storage properties about blend oil, soybean oil and canola oil were selected to be the main base oil, peanut oil was added to improve the flavor, then DHA algae blend oil formula was designed and determined.a. Restrictive model based on the Chinese residents’ actual dietary survey was:saturated fatty acids n-6 polyunsaturated fatty acids and n-3 polyunsaturated fatty acids b. Restrictive model based on the Chinese residents’ dietary guidelines was:saturated fatty acids polyunsaturated fatty acids and n-3 polyunsaturated fatty acids Variables in the above model are as follows:xi,the content of the No.i, vegetable oil in formula; Si, saturated fatty acid contents in the corresponding oil, Ni, n-6 polyunsaturated fatty acid contents in the corresponding oil, Ni, n-3 polyunsaturated fatty acid contents in the corresponding oil. The formula which balanced nutrition and satisfied the DHA intakes was:soybean oil 40%, canola oil 50%, peanut oil 4%, flaxseed oil 3%, DHA algae oil 3%. The formula had good cooking properties and storage stability. After cooking, the index values were as follows:acid values (0.20～0.42 mgKOH/g), peroxide values (1.96～2.62 mmol/kg), DHA loss (7.47%～8.96%), the oxidation induction time (4.25 h). The results of accelerated oxidation (39 d) by oven were as follows:acid values (0.17～0.40 mgKOH/g), peroxide values (1.50～28.95 mmol/kg), DHA loss (23.70%). The results of 63 d light-storage were as follows:acid values (0.23～0.37 mgKOH/g), peroxide values (1.50～4.80 mmol/kg), DHA loss (1.85%～2.68%).