The Use of Fermented Whey as a Coagulant in Tofu Industries

Fermented whey （a by-product from tofu industry） has been used as a coagulant in tofu manufactures in Indonesia. This research aimed to study effects of fermented whey on coagulation efficiency and physicochemical characteristics of tofu, compared to other acid coagulants （acetic acid and glucono-delta-lactone （GDL）） and salt coagulants （calcium sulfate and natural gypsum）. A randomized block design with a single factor was used in this research. Fermented whey could be used as coagulant in tofu manufacturing. Physicochemical characteristics of tofu from fermented whey were not significantly difference compared to tofu from calcium salt and acid coagulants. Coagulation efficiencies （CF, TSIL TPR and TB~） of fermented whey are lower than that from calcium salt coagulants （calcium sulphate and natural gypsum）. Fermented whey showed no significant differences in tofu properties and parameters of coagulation process, compared to GDL and acetic acid.

酸浆豆腐后熟过程中风味物质的形成途径分析

采集不同后熟阶段的酸浆豆腐为样本,对其游离氨基酸、有机酸、挥发性风味物质进行测定。结果显示,游离氨基酸和有机酸是滋味物质的主要来源,其中酸味氨基酸是主要的呈味物质,在不同的后熟阶段占总氨基酸的33%~35%。后熟过程中乳酸、乙酸和柠檬酸3种有机酸是主要呈味物质且含量最高,其总量约占有机酸总量的50.08%~65.00%。后熟过程中共检测到84种风味化合物,包括醛类、醇类、酚类、呋喃类等化合物,共同赋予酸浆豆腐独特的酵香风味。

豆清发酵液点浆工艺研究

利用豆清发酵液作为豆腐凝固剂进行点浆生产豆腐。通过单因素试验确定豆清发酵液总酸含量,豆清发酵液添加量和点浆温度为影响因素,以感官评分和弹性为响应值,采用响应面法对试验设计进行优化。结果表明,豆清发酵液点浆的最佳工艺条件为:豆清发酵液总酸含量5.3g/kg,豆清发酵液添加量29%,点浆温度76℃,在该条件下得到的豆腐感官评分为(76.20±0.36)分,豆腐弹性为0.95±0.01。

一株高产酸乳酸菌的分离鉴定及生物学特性研究

利用MRS选择性培养基从豆清发酵液中分离筛选乳酸菌。经初筛得到5株乳酸菌,通过比较不同乳酸菌在同一条件下的p H和产乳酸量复筛得到一株产酸较高、p H较低的优势产酸乳酸菌,对其编号为M-6。根据菌株的形态学观察、生理生化试验以及16S r RNA基因序列分析鉴定,初步将该菌株鉴定为肠膜明串珠菌(Leuconostoc mesenteroides strain M-6)。对其进行生物学特性研究,发现菌株M-6的最适生长温度在30℃,适宜p H范围为5.5~8.5,菌株在该温度下发酵20 h后菌液OD600nm高达1.2917,p H低至4.16(总酸),且菌株M-6有一定的耐盐受性,当Na Cl浓度大于3%时,菌株生长受到明显抑制。因分离得到的肠膜明串珠菌M-6具有较强的产酸能力,可利用其发酵制备豆腐凝固剂,在豆制品生产领域具有良好的应用前景。