物理预处理—可控酶解联合改性蚕蛹蛋白的研究
发布时间：2019-06-18 17:22
【摘要】：我国蚕业历史悠久,是世界上最大的蚕丝产地。由于传统的栽桑养蚕以获取蚕丝为主要目的,蚕蛹就成了主要副产品,我国每年可产新鲜蚕蛹50万吨以上,相当长的一段时期内蚕蛹基本上都被用作饲料,导致了巨大资源浪费。为了提高蚕蛹蛋白的利用价值,本研究采用微生物发酵法对蚕蛹的异味进行脱除,之后利用超微粉碎处理-酶解和超声波处理-酶解联合改性的方法对蚕蛹蛋白进行功能特性的改良,并研究改性前后的营养价值和生物学活性,为高附加值利用蚕蛹提供理论依据。以发酵后蚕蛹的异味物质为指标,从8种菌株中筛选出的白色假丝酵母的异味脱除效果最好;通过单因素试验,筛选出了最佳接种量为2%,最佳发酵温度为35℃,最佳发酵时间为40h;通过GC-MS对不同发酵工艺下蚕蛹的气味物质进行了分析,结果显示经发酵后蚕蛹的异味成分基本检测不到。经过微细化处理、酶解处理和微细化-酶解处理后,蚕蛹蛋白的溶解度分别为未处理的1.84、2.32和2.69倍,乳化性分别提高3.6%、15.05%和21.52%,起泡性及起泡稳定性也不同程度地得到提高。此外,经微细化处理后蚕蛹蛋白的水解度可达到22.59%,为未处理的1.58倍,蛋白回收率可达到56.68%,为未处理的1.82倍。不同处理改性的蚕蛹蛋白的分子变小,二硫键含量最高可降低19.70%,巯基含量最高可升高55.30%。改性后蚕蛹蛋白二级结构发生巨大变化,其中α-螺旋、β-折叠和β-转角等结构极度减少,无规则卷曲结构大量增加,最终蛋白的二级结构以无规则卷曲为主。经过超声波处理、酶解处理和超声波-酶解处理后,蚕蛹蛋白的溶解度分别为未处理的2.03、2.32和3.59倍,乳化性分别提高10.94%、15.05%和40.4%,起泡性及起泡稳定性也不同程度地得到提高。此外,经超声波处理后蚕蛹蛋白的水解度可达到24.55%,为未处理的1.72倍,蛋白回收率可达到75.99%,为未处理的2.44倍。不同处理改性的蚕蛹蛋白的分子变小,二硫键含量最高可降低20.39%,巯基含量最高可升高59.59%。改性后蚕蛹蛋白二级结构发生巨大变化,其中α-螺旋、β-折叠和β-转角等结构极度减少,无规则卷曲结构大量增加,最终蛋白的二级结构主要是无规则卷曲。改性后蚕蛹蛋白的氨基酸分析、营养学评价,抗氧化活性、体外血管紧张素转化酶(ACE)抑制率和促小鼠脾细胞增殖能力等研究结果表明,改性后蚕蛹蛋白的必需氨基酸(EAA)与非必需氨基酸(NEAA)的比值(EAA/NEAA)相比未处理蚕蛹蛋白提高了10%以上,均达到了理想蛋白模式,最高值达到了66.86%;必需氨基酸/总氨基酸的比值也均高于联合国粮食及农业组织/世界卫生组织(FAO/WHO)推荐模式的36%,氨基酸评分(AAS)及必需氨基酸指数(EAAI)也都得到了一定程度的提高,EAAI值均高于90%。改性后蚕蛹蛋白的1,1-二苯基-2-三硝基苯肼(DPPH)清除率最高达70%,亚铁离子的螯合率最高达到80%,总还原力也有较大的提升,相比未处理蚕蛹蛋白,改性后蚕蛹蛋白的抗氧化能力得到显著提升。改性后蚕蛹蛋白对血管紧张素转化酶(ACE)抑制率的IC50最低为2.00mg/mL,仅为未处理的5.93%。在剂量为50μg/mL时,改性后蚕蛹蛋白促小鼠脾细胞增殖能力可增加100%。说明改性后蚕蛹蛋白的营养价值、抗氧化活性、体外ACE抑制率以及促小鼠脾细胞增殖能力都得到了较为明显地提高。
[Abstract]:China's silkworm industry has a long history and is the world's largest silk production area. Due to the traditional mulberry-growing silkworm to obtain silk as the main purpose, the silkworm chrysalis is the main by-product, and the silkworm chrysalis can produce more than 500,000 tons of fresh silkworm chrysalis per year, and the silkworm chrysalis is basically used as a feed for a long period of time, leading to a great resource waste. in order to improve the utilization value of the silkworm chrysalis protein, the research adopts a microbial fermentation method to remove the peculiar smell of the silkworm chrysalis, And the nutritional value and the biological activity before and after modification are studied, and the theoretical basis is provided for the use of the silkworm chrysalis for high added value. The peculiar smell removal effect of Candida albicans from 8 strains was the best, and the optimal fermentation temperature was 35 鈩，
本文编号：2501657
[Abstract]:China's silkworm industry has a long history and is the world's largest silk production area. Due to the traditional mulberry-growing silkworm to obtain silk as the main purpose, the silkworm chrysalis is the main by-product, and the silkworm chrysalis can produce more than 500,000 tons of fresh silkworm chrysalis per year, and the silkworm chrysalis is basically used as a feed for a long period of time, leading to a great resource waste. in order to improve the utilization value of the silkworm chrysalis protein, the research adopts a microbial fermentation method to remove the peculiar smell of the silkworm chrysalis, And the nutritional value and the biological activity before and after modification are studied, and the theoretical basis is provided for the use of the silkworm chrysalis for high added value. The peculiar smell removal effect of Candida albicans from 8 strains was the best, and the optimal fermentation temperature was 35 鈩，
本文编号：2501657
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