干酪乳杆菌产β-甘露聚糖酶发酵条件优化及在果汁澄清中的应用

为丰富甘露聚糖酶在乳酸菌中的菌株来源，扩大甘露聚糖酶在食品级领域的应用。通过形态观察、API 50 CHL试剂条检测和16S rDNA序列分析，对产β-甘露聚糖酶的乳酸菌进行鉴定。结果表明，鉴定出一株产β-甘露聚糖酶的干酪乳杆菌（Lactobacillus casei）3MP-5-3。采用响应面法获得最优培养基组分为角豆胶5.7 g/L、酵母提取物5.2 g/L、葡萄糖8.0 g/L、蛋白胨10.0 g/L、牛肉膏10.0 g/L、柠檬酸铵3.0 g/L、1 mL吐温80和初始pH值6.1。优化后菌株产甘露聚糖酶酶活从（64.55±0.20） U/mL增加到（75.83±0.31） U/mL，是优化前的1.17倍。β-甘露聚糖酶能提高苹果、橙子、桃子、柿子和蓝靛果5种果汁出汁率和澄清度。其中酶处理组的柿子汁（44.53%）和苹果汁澄清度（73.60%）显著高于离心组（36.86%和64.41%）（P＜0.05），分别提高了17.2%和14.3%。该结果表明干酪乳杆菌3MP-5-3粗甘露聚糖酶在果汁澄清具有经济、简便的应用潜力。

Optimization of fermentation conditions and application in fruit juice clarification of β-mannanase from Lactobacillus casei

In order to enrich the strain source of mannanase in lactic acid bacteria and expand the application of mannanase in the field of food grade, the β-mannanase-producing strain was identified. Results showed that a strain of β-mannanase-producing Lactobacillus casei 3MP-5-3 was identified by morphological observation, API 50 CHL reagent strip detection and 16S rDNA sequence analysis. The optimal fermentation conditions obtained by response surface methodology were carob gum 5.7 g/L, yeast extract 5.2 g/L, glucose 8.0 g/L, peptone 10.0 g/L, beef extract 10.0 g/L, ammonium citrate 3.0 g/L, Tween 80 1 ml and initial pH 6.1. After optimization, the activity of mannanase produced by the strain increased from (64.55±0.20) U/ml to (75.83±0.31) U/ml, which was 1.17 times of that before optimization. The β-mannanase could improve juice yield and clarity of apple, orange, peach, persimmon and indigo fruit juice. Among them, the clarity of persimmon juice (44.53%) and apple juice (73.60%) in enzymatic treatment group was significantly higher than that in centrifugal group (36.86% and 64.41%) by 17.2% and 14.3%, respectively (P＜0.05). The results indicated that crude mannanase produced by L. casei 3MP-5-3 had economic and simple application potential in juice clarification.