功能性肉品发酵剂的筛选及接种发酵对香肠抗氧化肽形成机制研究

Fermented sausage is a typical of traditional Chinese fermented meat products. Oxidation of lipid usually occurs during the storage of fermented sausages because its moisture content is low while the fat content is high. When the oxidation reaches the level of rancidity, the product is unacceptable for consumer. In previous work, the peptides isolated from the traditional fermented sausage were found to have 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. The result showed that the antioxidant peptide had been produced during the ripening of fermented sausage. Whereas to date, little has been reported about the changes of antioxidant peptide formed during the ripening of fermented sausage and effect of antioxidant peptide on the sausage quality.The aim of this study is to creening the functional meat starter cultures and optimizing the parameters of fermented sausage inoculated with these starter cultures. On this basis, with the protein electrophoresis, ultrafiltration, ion exchange chromatography, liquid chromatography tandem mass spectrometry(LC-MS/MS), mid infrared spectroscopy (MIR), etc., systematic research will be performed to find out that the effect of starter cultures on the content and antioxidant activity of antioxidant peptide, the purification and characterization of antioxidant peptide, molecular structures of antioxidant peptide, and the effect of antioxidant peptide on the sausage quality during the ripening of fermented sausage. The results above will contribute to demonstrate the mechanism of antioxidant peptide produced during the ripening of fermented sausage, and thus provide data for improving the quality of fermented sausage.

发酵香肠是我国传统发酵肉制品的典型代表，由于其水分含量较低，而脂肪含量较高，在贮存过程中脂肪容易氧化酸败，最终造成消费者可接受程度的降低。前期研究中，发现从传统的发酵香肠中分离到的肽具有一定的清除DPPH自由基的能力，说明香肠在发酵成熟过程中产生了抗氧化肽，但目前对抗氧化肽形成变化的规律以及其对香肠品质影响的研究还鲜见报道。本项目旨在筛选优良的功能性肉品发酵剂，并优化接种发酵香肠的工艺参数。在此基础上，借助于蛋白质电泳、超滤、离子交换层析、液相色谱串联质谱（LC-MS/MS）、中红外光谱（MIR）等生物技术，系统地研究香肠发酵成熟过程中：发酵剂对抗氧化肽的含量与性能影响及变化规律；分离纯化抗氧化肽的方法；抗氧化肽分子结构特征；抗氧化肽对发酵香肠品质的影响等。以上研究可以基本阐明发酵香肠成熟过程中抗氧化肽的形成机制，从而为改善发酵香肠的品质提供理论依据。

发酵香肠是我国传统发酵肉制品的典型代表，由于其水分含量较低，而脂肪含量较高，在贮存过程中脂肪容易氧化酸败，最终造成消费者可接受程度的降低。本项目从12份传统中式香肠样品中筛选出蛋白酶活性较强且具有益生特性和安全性的菌种作为发酵剂，并用响应面法对发酵工艺条件进行优化，探讨发酵剂对香肠抗氧化及品质的影响。通过发酵香肠体系及体外模拟体系，研究了混合发酵剂植物乳杆菌 CD101和模仿葡萄球菌 NJ201在加工的各个阶段对蛋白质的降解以及多肽抗氧化能力的变化情况。在此基础上，借助超滤、分子筛层析和反相-高效液相色谱法纯化了发酵香肠肽，利用液相色谱-串联质谱鉴定肽序列并对其进行人工合成及活性验证。通过研究，分别筛选出了8株蛋白酶活性较强且具有益生特性和安全性的乳酸菌和葡萄球菌，这些菌株可以作为肉品发酵剂用于工业生产。添加植物乳杆菌和模仿葡萄球菌为混合发酵剂，接种量为10的7次方CFU/g、复配比例1:1、发酵温度30℃，此时感官评分为85.28分，与模型理论值接近，为最佳工艺参数。使用该组发酵剂不仅能够在一定程度上抑制脂肪和蛋白的氧化，而且能明显改善香肠的色泽、品质和风味，提升产品的营养价值和安全性。使用该发酵剂能有效促进多肽生成，增强干发酵香肠中多肽，特别是小分子多肽的抗氧化能力，有助于从干发酵香肠自身内部提高抗氧化能力，延长产品的货架期。肽段SDEEVEH和FAGDDAPR表现出较强的DPPH自由基清除活性，肽段PPAPP具有较高的FRAP值，肽段EPPVT、ALELDSNLYR和QEYDESGPSIVHR表现出较强的ABTS+·自由基清除率。.以上研究可以基本阐明发酵香肠成熟过程中抗氧化肽的形成机制，从而为改善发酵香肠的品质提供理论依据。