Kurdi Peter, Chaowiwat Patspon, Weston Jirathit, Hansawasdi Chanida
Food Science and Technology, Science Division, International College, Mahidol University, Buddhamonthon 4 Rd, Nakhonpathom, Salaya 73170, Thailand.
Int J Food Sci. 2021 Mar 23;2021:5580976. doi: 10.1155/2021/5580976. eCollection 2021.
This research investigated the microbial quality and the protein contents of Thai commercial frozen products of silkworm (), bamboo caterpillar (), and field cricket (). Total mesophilic aerobic counts were about 8-8.4 log cfu/g, while lactic acid bacteria numbers were up to 5.2 log cfu/g samples. Yeasts and mold as well as numbers were found to be no more than 6.3 and 6.6 log cfu/g, respectively, while spp. enumeration detected 3.2-3.6 cfu per gram frozen insect samples. The protein content in cases of cricket and bamboo caterpillar after the Soxhlet defatting method and the Folch lipid extraction combined with isoelectric point precipitation were similar when compared at pH 3.5 or pH 4.5. In contrast, the protein yield from silkworm was higher at pH 3.5 in the Soxhlet defatted sample, as opposed to the Folch method treated sample where higher protein yield was obtained at pH 4.5. Furthermore, 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) of field cricket subcritical water (121 or 135°C for 15 or 30 minutes) hydrolysates were also measured on a pilot basis. These tests revealed higher antioxidant activities in treated samples than in the untreated control. The highest DPPH radical scavenging activity and FRAP values were detected in samples treated at 135°C, while the protein content of these samples was lower than that of the untreated control. These results indicate that hydrolytic compounds of proteins and probably other types of cricket materials are possibly involved in the antioxidant activities of the treated defatted cricket samples.
本研究调查了泰国商业化冷冻蚕、竹节虫和田蟋蟀产品的微生物质量和蛋白质含量。总嗜温需氧菌数约为8 - 8.4 log cfu/g，而乳酸菌数高达5.2 log cfu/g样品。酵母和霉菌以及其他菌数分别不超过6.3和6.6 log cfu/g，而每克冷冻昆虫样品中检测到的其他菌数为3.2 - 3.6 cfu。采用索氏脱脂法以及福尔克脂质提取结合等电点沉淀法处理后，在pH 3.5或pH 4.5条件下比较，蟋蟀和竹节虫的蛋白质含量相似。相比之下，索氏脱脂样品在pH 3.5时蚕的蛋白质产量较高，而福尔克法处理的样品在pH 4.5时获得较高的蛋白质产量。此外，还初步测定了田蟋蟀亚临界水（121或135°C，15或30分钟）水解产物的2,2 - 二苯基 - 1 - 苦基肼（DPPH）自由基清除活性和铁还原抗氧化能力（FRAP）。这些测试表明，处理后的样品比未处理的对照具有更高的抗氧化活性。在135°C处理的样品中检测到最高的DPPH自由基清除活性和FRAP值，而这些样品的蛋白质含量低于未处理的对照。这些结果表明，蛋白质的水解化合物以及可能其他类型的蟋蟀物质可能参与了处理后的脱脂蟋蟀样品的抗氧化活性。
