乳酸乳球菌豆腐生物凝固剂性能评价研究

以乳酸乳球菌乳亚种为发酵菌株,大豆黄浆水为培养基质,制作生物凝固剂;以生物凝固剂豆腐的感官指标、凝胶强度、得率和持水率为评价标准,探讨纯种乳酸菌豆腐生物凝固与传统黄浆水自然发酵凝固剂对豆腐品质的影响。结果表明:乳酸乳球菌乳亚种生物凝固剂制作的豆腐感官评分为9.7分,凝胶强度为614.39 MPa,得率为151.08 g/100 g,持水率为95.47%,综合评分为227.96,凝固效果显著优于黄浆水自然发酵凝固剂。     

山楂酸豆腐凝固剂的应用工艺研究

利用山楂中的酸性成分研制新型豆腐凝固剂。通过超声辅助水浴法提取总酸,经旋转蒸发浓缩,作为新型豆腐凝固剂。在单因素实验基础上以保水性、产品得率为指标,进行正交实验确定凝固剂的最优添加条件为0.25g·100mL-1豆浆、豆浆豆水比(m/v)为1∶9、点浆温度为60℃,在此条件下制备的豆腐保水性较好,产品得率较高,为250.42%,其保水性为29.77%。     

新型W/O盐卤凝固剂对大豆蛋白凝胶中水分变化的影响

探讨新型油包水(W/O)盐卤凝固剂对大豆蛋白凝胶中水分变化的影响。利用差示量热扫描仪(DSC)和低场核磁共振(LF-NMR)来研究豆腐凝胶过程中水分的变化。结果表明,在豆腐凝固的过程中,总水分含量下降,自由水下降,结合水含量总体呈现上升趋势,豆腐凝胶结构中的水分自由度在不断减少。与传统盐卤凝固豆腐相比,新型W/O盐卤豆腐凝胶在同一阶段的自由水含量较高,弛豫时间较长,W/O凝固剂的缓释可以改善豆腐的质量。此外,WPI含量不仅对乳液稳定性起作用,而且会改善豆腐品质。在0.5%WPI W/O乳液作为凝固剂得到的豆腐样品核磁共振成像中氢质子的密度最大,说明WPI可以提高豆腐的持水性和品质,因此可将0.5%WPI制备的W/O乳液凝固剂作为豆腐生产用凝固剂。     

凝固剂对白玉饺品质特性的影响

为丰富豆腐深加工产品的形式,以豆腐为饺皮、猪肉为馅料制备一种特色传统豆腐菜肴——白玉饺,并比较凝固剂种类对白玉饺质构(Texture Profile Analysis,TPA)、色泽、感官特性、持水性以及基本营养成分(水分、粗蛋白、粗脂肪、灰分)的影响。结果表明:盐卤、石膏和内酯(GDL)制备白玉饺皮的最适添加量分别为2.5,2.5,2.0g/100g干豆;石膏白玉饺与内酯白玉饺持水性无显著差异(P0.05),但显著(P0.05)高于盐卤白玉饺(62.89%),且硬度(石膏白玉饺和内酯白玉饺分别为760.88,745.08g)显著小于盐卤白玉饺(861.86g),而咀嚼性、回复性、凝聚性、黏附性方面无显著差异(P0.05);石膏白玉饺的a*值显著(P0.05)低于盐卤和内酯白玉饺,但亮度值L*值无显著(P0.05)差异;石膏白玉饺在折叠破碎情况、口感细腻和外形等感官特性方面优于盐卤和内酯白玉饺。因此,可选择2.5g/100g干豆的石膏作为特色菜肴白玉饺加工的凝固剂。     

酶解花生壳制备低聚木糖的研究

以花生壳为原料,在固液比1∶20,H_2SO_4浓度为1.0%,120℃条件下处理30min,木聚糖提取率为40.1%。利用木聚糖酶降解木聚糖制备低聚木糖,确立了酶解工艺条件:50℃,pH4.8,加酶量2%(相对固体花生壳原料).搅拌速度80r/min,反应时间24h。在上述反应条件下,低聚木糖得率为81.2%。     

Colletotrichum lini ST-1静息细胞转化DHEA制备7α，15α-diOH-DHEA的工艺

利用亚麻刺盘孢(Colletotrichum lini ST-1)静息细胞转化去氢表雄酮,制备三羟基雄甾烯酮,通过单因素优化确定了最佳摇瓶转化条件:细胞质量浓度为12 g/L,p H值为6.5,装液量为30 m L/250 m L,转速为220 r/min,温度为30℃。在上述条件下,底物投料质量浓度为10 g/L时,转化48 h,产物摩尔得率为38.5%,较生长细胞提高了21.0%。在上述工作基础上,尝试了静息细胞连续批次转化,最终通过两批次的连续转化,在底物累计投料质量浓度为18 g/L时,转化78h,产物的累积质量浓度高达12.1 g/L,产物摩尔得率可达60.5%。     

以氯化镁为凝固剂的全豆充填豆腐质构与流变特性研究

以氯化镁为凝固剂、谷氨酰胺转氨酶为助凝剂,采用复合超微粉碎技术,制备全豆盐卤充填豆腐,并探究了该豆腐凝胶形成过程中的质构特性与流变特性。结果表明:在氯化镁浓度为0.4%(w/w)、谷氨酰胺转氨酶浓度为7U/g(蛋白质)时,全豆盐卤充填豆腐成型完好,凝胶强度最大达到221g,是传统内酯充填豆腐的2.2倍;持水率比传统内酯充填豆腐略小,为70%。在低剪切力阶段,全豆豆浆的粘度远大于传统豆浆,在全豆盐卤充填豆腐形成过程中,与传统内酯充填豆腐类似,储藏模量G′值迅速上升,但全豆盐卤充填豆腐G′值最终达到3020Pa,而传统内酯充填豆腐G′值最终仅为1300Pa。与传统内酯充填豆腐类似,全豆盐卤充填豆腐凝胶形成过程中损耗模量G″值随着时间的变化趋势基本与G′值类似,但是G″值远远小于G′值,表明在全豆盐卤充填豆腐全凝固过程中形成了典型的弹性凝胶。此外,豆腐凝胶微观结构观察表明全豆盐卤充填豆腐凝胶网络结构没有传统内酯充填豆腐紧密,且有纤维嵌套,从微观上解释了全豆盐卤充填豆腐持水率略低的现象。     

肉类工业废水的混凝沉淀法处理工艺优化

采用混凝沉淀法预处理屠宰废水,取得了良好的处理效果,COD、油的去除率分别可达72%、80%.实验确定混凝的最佳工艺条件为PFC加入量0.6 ml,沉降时间20 min,搅拌强度120 r/min,搅拌时间90 s.     

复合凝固剂在黑豆豆腐加工中的应用

为确定黑豆豆腐的最佳工艺条件,以黑豆和水为主要原料,通过单因素及正交试验考察复合凝固剂质量比、料液比、凝固温度及凝固时间对黑豆豆腐的感官品质、质构特性、色泽、含水率、蛋白质含量及脂肪含量的影响,确定最佳参数。结果表明：黑豆豆腐最佳工艺条件为复合凝固剂质量比（谷氨酰胺转氨酶：硫酸钙）1∶3.00、料液比1∶8.0（g/mL）、凝固温度78℃、凝固时间27 min。此条件下黑豆豆腐的感官评分为93.0,含水率为60.8%,蛋白质含量为16.7%,脂肪含量为8.2%。     

低盐卤用量腐乳白坯自动化生产关键工艺

以大豆为原料对腐乳生产中泡豆、点卤等关键生产工艺参数进行优化,构建了腐乳白坯标准化、自动化、关键节点协调一致的具有低盐卤用量的腐乳白坯加工工艺,其关键工艺技术参数为:豆水比例1∶3.5(g∶m L)泡豆12 h;干大豆按豆水质量比1∶7的比例磨浆;20 min将生豆浆煮沸到100℃,闷浆5~10 min;82~86℃下35r/min搅拌30 s(点卤时间20 s)以盐卤与添加豆浆的质量的1.2%进行点卤。该工艺的最大特征是低盐卤用量,且腐乳水分自由度比发酵前的腐乳白坯明显降低,有利于品质和保藏,可以实现腐乳白坯的全自动加工。     

Yield and Textural Properties of Soft Tofu as Affected by Coagulation Method

Soft tofu was made using two coagulants (calcium sulfate and modified nigari), three stirring speeds (137, 207, and 285 rpm), and six stirring times (5, 10, 15, 20, 25, and 30 sec). The lowest stirring speed, 137 rpm, did not coagulate the soymilk. Tofu made by the highest stirring speed (285 rpm) had a lower yield, but higher brittleness force, hardness and elasticity than tofu made at 207 rpm. Tofu made from modified nigari had lower textural parameter values than those made from calcium sulfate. Yield of tofu made from both coagulants stirred at 207 or 285 rpm decreased as stirring time increased to 30 sec. Textural properties were related to stirring time. Stirring time < 25 sec was appropriate for soft tofu making.     

溶剂介质法制备碱式氯化镁晶须的工艺研究

以氯化镁为原料,研究了溶剂介质法制备碱式氯化镁晶须的影响因素.详细考察了有机溶剂的种类、陈化时间和搅拌速度对氯化镁晶须复合材料制备的影响.根据SEM的测试图片结果显示,提出了制备氯化镁晶须复合材料的最佳工艺条件是：以乙醇为溶剂介质,搅拌速度120 r/min,陈化时间24h.     

高温杀菌对麻婆豆腐菜肴食用品质的影响

为研制常温长货架期的豆腐菜肴产品,以麻婆豆腐为对象,研究了不同高温杀菌温度及时间对产品品质的影响,对高温杀菌处理前后的麻婆豆腐进行了失水率、色泽、质构、感官评价等分析,在保证豆腐菜肴杀菌效果(F₀≥4.0)前提下,115、118、121 ℃所对应的适宜杀菌时间分别为28、17、14 min。麻婆豆腐失水率随着杀菌温度上升而增加,与115、118 ℃杀菌条件相比,121 ℃杀菌条件下失水率显著提高。经过杀菌后,豆腐的外部色泽变化较大,其中118 ℃下杀菌后豆腐颜色较好。此外,经过杀菌后,麻婆豆腐的硬度、咀嚼性、胶着性降低,但不同杀菌条件之间并无显著性差异。感官评价结果显示,不同杀菌条件之间并无显著性区别。因此,综合考察杀菌后麻婆豆腐各方面品质变化,确定118 ℃、17 min杀菌对麻婆豆腐效果最佳。     

Quality improvement of kenaf-based tofu: effects of kenaf seed substitution,and coagulant types and concentrations on the physicochemical quality,texture profile and microstructure of the tofu

Tofu was made by substituting kenaf seed (K) with soybean (S) at 100 (positive control), 50%, 40%, 30%, 20%, 10% and 0% (negative control). The results indicated that kenaf seed substitution at all ratios significantly increased the soluble solids and protein content of the milky extracts. The yield, moisture and protein content of the tofu were significantly increased with the increase in kenaf seed substitution, while the lipid content was significantly decreased. The tofu made with kenaf seed substitution of 50%, 40% and 30% had the same protein content (43.76–45.36 g/100 g) with the positive control (45.36 g/100 g), but a significantly higher lipid content (32.00–35.75 g/100 g) than that of the positive control (27.50 g/100 g). The microstructure of the tofu revealed that only the positive control had a honey-comb structure, whilst the tofu made from kenaf seed-soybean blends had a pseudo-honey like structure. Up to 30% of soybean can be added into the kenaf-based tofu, without any negative effect on the textural and colour properties and, protein content, but significantly improved the essential amino acids content of the kenaf-based tofu. Therefore, the blend of 70K:30S ratio using 0.5 g% glucono delta-lactone as a coagulant is recommended to produce kenaf seed-soybean tofu.     

Comparison of Two Small-Scale Processing Methods for Testing Silken Tofu Quality

In developing a simple, reliable, small-scale method to assess silken tofu quality in our soybean improvement program, we examined two processing methods and two coagulants, glucono-δ-lactone (GDL) or nigari (magnesium chloride) in two experiments. Silken tofu was prepared from a commercial soybean variety (expt 1) or seven soybean varieties (V1–V7) which were grown and harvested together (expt 2). The soybeans were soaked overnight (the soak method, with 55 g soybeans) or ground dry first (the dry method, with 60 g soybeans) before processing. The quality of the silken tofu was evaluated and compared among varieties and coagulant-processing methods and their interactions. Moisture and protein content in soymilk and soybean seeds, soymilk yield and protein and solid recovery in soymilk were determined. Compared with the dry method, the soak method allowed faster soymilk extraction, produced soymilk with lower solid and higher protein content and firmer silken tofu with either GDL or nigari as coagulant. Depending on whether nigari or GDL was used as coagulant, the soak method also produced silken tofu with the highest or the lowest water loss which correlated strongly and negatively with tofu hardness (r?=??0.93***). Differences were detected among varieties for the key quality attributes. Taken together, the soak method with GDL as coagulant would be the preferred combination to use to assess tofu quality.     

细菌纤维素在传统豆腐中的应用

目的：改善传统豆腐中纤维素含量及豆腐品质。方法：将细菌纤维素作为一种膳食纤维应用到传统豆腐加工中,研究其对传统豆腐凝胶强度、保水性、感官等品质特性的影响。结果：当细菌纤维素添加量为3.0g/100mL时,豆腐品质特性较好。豆腐凝胶强度为181g,失水率为17.2%,与未添加细菌纤维素豆腐样品相比,凝胶强度无显著变化,但失水率降低了9.5%。结论：添加细菌纤维素的豆腐质地细腻光滑,有弹性,无明显粗糙感,其膳食纤维含量得到进一步强化。     

Preparation of tofu using chitosan as a coagulant for improved shelf-life

The potential of chitosan as a coagulant in commercial tofu preparation was investigated with six chitosans of different molecular weights using various treatments. The following optimum processing conditions for tofu preparation were proposed: chitosan with a molecular weight of 28 kDa; chitosan solution type, 1% chitosan/1% acetic acid; chitosan solution to soymilk ratio, 1 : 8; coagulation temperature, 80 °C; coagulation time, 15 min. However, the sensory quality of tofu was notably improved using a 1 : 1 mixture of 1% acetic acid and 1% lactic acid instead of 1% acetic acid alone as a chitosan solvent. Tofu prepared with chitosan had lower ash and higher protein content than those of commercial products tested. In storage tests, the chitosan‐tofu had a longer shelf‐life, about 3 days, than tofu made with CaCl₂. This added shelf‐life is significant in view of the magnitude (366 000 tonnes year^?1) of tofu produced from commercial tofu plants (1407 plants as of 1998) in Korea.     

豆腐黄浆水资源综合利用研究进展

豆腐黄浆水是制备豆腐时所产生的副产物,在自然环境下酸化并常被用作豆腐凝固剂。该文综述了豆腐黄浆水中营养功能物质及其酸化过程中微生物群落的组成,并对豆腐黄浆水及其酸化微生物菌种资源在食品发酵领域的应用研究现状进行分析,为豆腐黄浆水的进一步开发利用提供理论基础和实践指导。     

豆腐凝胶形成影响因素的研究进展

豆腐是一种大豆蛋白质凝胶体。豆腐凝胶的形成受到多种因素的影响,本文从加工豆腐的原料、加工条件以及凝固剂三个主要的影响因素出发,综述了国内外对于豆腐凝胶形成影响因素的研究现状。旨在为豆腐的规模化、自动化生产提供有力的理论依据。并对今后豆腐凝胶的研究方向进行了展望。     

Coagulation of soymilk and quality of tofu as affected by freeze treatment of soybeans

The present study was carried out to investigate the effects of freezing of soybeans on the coagulation of soymilk and quality of tofu. Soymilk, prepared from frozen soybeans, was found to coagulate faster in the presence of coagulant and produced a more uniform-structured gel than that from unfrozen soybeans. Tofu, prepared from frozen soybeans, showed a more orderly and denser network structure than that from unfrozen soybeans, thereby inducing an increase in some textural parameters such as hardness, springiness, gumminess and chewiness as well as syneresis. Freezing also brought about some changes in tofu quality: lower yield, lower fat and higher protein contents. Results of sensory evaluation showed that tofu from frozen soybeans had better sensory properties in terms of flavour and mouthfeel. From these results, it was concluded that freezing promoted the coagulation process of soymilk and changed the quality of tofu in a positive way.