Orthogonal Design Method for Determination of Crude Fat Content in Peanut

Peanut is the main oil crop and economic crop in China, and its fat content is 45% to 55%. The level of fat in peanuts determines the quality of peanuts. If you want to know how much fat in peanuts, we can use the crude fat analyzer, which has a variety of models, such as SZF-06A fat analyzer, SZF-06B fat analyzer, SZF-06 fat analyzer. The fat content of peanut seeds is one of the important indicators to determine its quality, and it also directly affects the price of peanuts. There are many ways to determine the fat content, of which the traditional method is Soxhlet extraction. This method is a national standard method and it is also recommended by international standards. The sample was placed in an extraction tube and reflux distilled in a water bath to distill the condensed ether. When the crude fat content of the sample is high, it usually takes more than ten hours. This method is time consuming and laborious and cannot meet the requirements of rapid measurement. The measurement principle of the automatic fat analyzer is the hot-extraction-oil weight method. Since the sample is in a high-temperature solvent, the molecular motion is accelerated and the speed of fat leaching is accelerated, thereby greatly shortening the extraction time, thereby speeding up the determination of the sample. The complete extraction of the sample is generally completed in less than 2 h. Therefore, the automatic fat analyzer is quicker, safer, more economical and reliable than the traditional Soxhlet fat extractor, and has become an important tool for the determination of fats and oils. However, the instrument is less widely used in the determination of crude fat in peanut, the main oil crop, and its measurement method is not uniform. Due to the high fat content of peanuts, some users blindly lengthen the extraction time in order to pursue the reliability and accuracy of the results, so that the instrument's potential can not be fully exerted. In this paper, the three main factors affecting fat determination are optimized: temperature, extraction time and leaching time, in order to provide basis for improving the determination of fat content in peanut kernels.

1 Materials and Methods

1. 1 Petroleum ether with a boiling range of 30-60 °C (Analytical Pure).

1.2 FOSS2050 type fat analyzer; electronic analytical balance (accuracy 0.0001g), drying oven, small plant grinder.

1. 3 Sample preparation Take Huayu No. 20 seeds that have been dried at 105 °C for 8 h, cooled in a desiccator, and smashed into sealed bags.

1. 4 Orthogonal design extraction method According to the principle of hot-extraction and oil-gravimetry, the extraction temperature (A), extraction time (B) and elution time (C) are selected as the investigation factors, and each has 3 levels. , use L9 (34) orthogonal table for testing (see Table 1), repeated three times.

1.5 fat determination Weigh dried crushed peanut samples 1. 0000 ~ 2. 0000g (W0) in the dried filter paper tube, and cover the sample with a layer of dry absorbent cotton, put the filter paper tube into the fat analyzer. . The aluminum cup is dried to constant weight at 105 °C and weighed (W1), placed on the instrument heating plate, and the instrument is connected to the handle, so that the aluminum cup is tightly connected with the refluxer. Add 80 mL of petroleum ether from the addition port and connect the condensate. According to Table 1, set the extraction conditions: heating temperature (105 °C, 120 °C, 135 °C), extraction time (40 min, 60 min, 80 min), rinsing time (35 min, 30 min, 25 min), reagent recovery 15 min, evaporated to dryness for 3 min. After the end of the procedure, the aluminum cup was removed and dried in an oven at 105° C. for 0.5 to 1 h, cooled in a desiccator and weighed (W2).

1.6 Data Analysis Crude Fat Content (%) = (W2 - W1) ×100/W0. The statistical analysis of the orthogonal test results refers to the results of the orthogonal observations of the repeated observations edited by Ming Daoxu, using the new complex-difference method. Multiple comparisons are done on DPS 7.05.

2 Results and Analysis

An intuitive analysis of the crude fat content data (Table 2) compares the extremes of the three factors (R) and shows that RC (1.1219) > RB

(0. 8468) > RA (0. 1343), ie, the rinsing time has the greatest influence on the determination result, followed by the leaching time, and the influence of the extraction temperature is the smallest. Analysis of variance showed that (Table 3), factor B (leaching time) and factor C (rinsing time) had significant differences among levels, and factor A (extraction temperature) had no significant differences among levels. Since the difference in factor A levels was not significant, combining B and C factor mean and significance test results (Table 4), B3C3 and B3C2 should be better extraction schemes. They correspond to Process 3 (A1B2 C3) and Process 6 (A2B3 C2) and are located in the fourth and first places in the 9 processes (Table 5). To sum up, A2B3 C2 should be the optimal combination, namely the extraction temperature 120 °C, extraction time 80 min, rinse time 30 min for the best extraction of peanut fat.

3 Summary

In this paper, FOSS2050 automatic fat analyzer was used to optimize the three important factors (leaching temperature, extraction time and elution time) affecting the determination of crude fat content in peanuts by orthogonal design method. The results showed that the extraction temperature was 120 °C. , Extraction time 80min, rinse time 30min is the best extraction program for peanut fat. Li Liang used the ZF2001 fat analyzer to conduct experiments with different extraction times (10 to 90 minutes). When the extraction time was 70 minutes, more than 99.5% of the extraction rate was achieved, and the extraction rate reached 80 minutes. The highest, which is very consistent with the experimental results. In this experiment, the extraction rate of crude fat from peanut kernels was not discussed. This needs to be further studied in the future.