作　　者： ; ; ; ; ; ;

机构地区： 广东省农业科学院

出　　处： 《农业工程学报》 2016年第z2期

摘　　要： 为筛选出适合龙眼发酵的复合乳酸菌，优化建立其发酵工艺，比较分析了7种不同的乳酸菌发酵龙眼的降糖能力和释放结合态酚类物质的能力，发现明串珠菌降糖能力最强，植物乳杆菌释放结合态酚能力最强。利用植物乳杆菌和明串珠菌复合发酵龙眼果肉，以游离酚质量分数和还原糖质量分数结合的综合模糊评判值为指标，通过Box-benhnken中心组合试验设计，确定复合乳酸菌发酵龙眼的最佳工艺条件。结果表明，各因素对复合乳酸菌发酵龙眼果浆的模糊评判值影响程度从强到弱依次为：发酵时间>发酵温度>接种量>料液比。复合乳酸菌发酵龙眼的最佳工艺为：料液比为1∶7（g/mL），发酵温度为37℃，发酵时间为53 h，接种量为1.4%，菌种配比为1∶1。在最佳工艺条件下，发酵龙眼果浆的游离酚质量分数为（161.77±3.93） mg/(100 g)，还原糖质量分数为（122.80±3.64） mg/g。该研究为开发低糖含量，且适合糖尿病、肥胖症等病人食用的龙眼乳酸菌发酵饮料新产品提供参考。 Longan (Dimocarpus longan Lour.) is a subtropical fruit, and it contains many nutritional and functional components such as carbohydrates, fiber, and phenolics. However, the fresh longan fruit is susceptible to spoilage and has a short storage life, so it is necessary to develop a new product of longan by fermentation. The purpose of this study was to obtain the complex lactic acid bacteria being suitable for fermentation of dry longan pulp, and the optimizaiton of process conditions of fermentation. The effect of seven lactic acid bacteria (Lactobacillus acidophilus,Leuconostoc mesenteroides, Lactobacillus casei,Pediococcus pentosaceus,Lactobacillus plantarum subsp·Plantarum,Lactobacillus delbrueckii subsp. lactis ) fermentations on the Lactobacillus colonies, the pH value, the acidity and the content of reducing sugar and free phenolic was analyzed. The result showed that the content of reducing sugar was consumed and the content of free phenolic was increased in seven lactic acid bacteria fermentations in dry longan pulp.Leuconostoc mesenteroides and Lactobacillus plantarumsubsp·Plantarum were selected by comparing the effect of seven lactic acid bacteria fermention. The conditions of longan pulp fermented by complex lactic acid bacteria were optimized through the single factor experiment, and factors included solid-liquid ratio, fermentation temperature, fermentation time, complex lactobacillus inoculation, complex lactobacillus matching shift. The result showed that solid-liquid ratio, fermentation temperature, fermentation time, and complex lactobacillus inoculation were significant influence factors in dry longan pulp fermented by complex lactic acid bacteria. And the suitable conditions in dry longan pulp fermented by complex lactic acid bacteria were solid-liquid ratio1:7 (g/mL), fermentation temperature 35℃, fermentation time 48 h, complex lactobacillus inoculation 1%. Complex lactobacillus matching shift could not significantly effect on the fuzzy evaluation value in dry longan pulp fermented by complex lactic acid bacteria, which synthetically expressed the changing situation of the content of free phenolics and sugar in dry longan pulp. The conditions of longan pulp fermented by complex lactic acid bacteria were optimized through Box-Benhnken central composite experimental design based on the indicators of the fuzzy evaluation value. A regression model of four factors including the fermentation time, the mixed lactobacillus inoculation, solid-liquid ratio and the fermentation temperature was established. Through regression analysis and validation test, the optimum conditions were solid-liquid ratio1:7 (g/mL), fermentation temperature 37℃, fermentation time 53 h, complex lactobacillus inoculation 1.4%, complex lactobacillus matching shift 1:1. These four factors which impacted on the free phenolics and reducing sugar content in descending order were fermentation time, fermentation temperature, complex lactobacillus inoculation and solid-liquid ratio. Fermentation time and fermentation temperature were significant interaction terms. Complex lactobacillus inoculation and fermentation time were significant interaction terms. The fuzzy evaluation value prepared under the optimum conditions was 89.32, and the relative error was 2.70% between predictive fuzzy evaluation value (91.80) and true fuzzy evaluation value. The free phenolics and reducing sugar content prepared under the optimum conditions respectively were (161.77±3.93) mg/(100 g), (122.80±3.64) mg/g. This research provides a theoretical guidance for the development of longan beverage fermented by lactic acid bacteria, which contains the lower sugar content and is suitable for some patients with diseases such as diabetes and obesity.

关 键 词： 工艺 优化 发酵 龙眼 乳酸菌 还原糖 游离酚

分 类 号： [TS255.36]

领　　域： [轻工技术与工程] [轻工技术与工程]