我国糙米酵素的研究进展

糙米酵素是在糙米中加入少量蜂蜜,经活性面包干酵母等发酵剂发酵得到的一种功能性食品基料(其中含有各种酶),文章综述了糙米酵素的营养与保健作用、发酵剂中微生物的分离筛选、发酵工艺以及糙米酵素的应用等方面的研究进展,并展望了中国糙米酵素开发应用的广阔前景.     

糙米酵素的功能与开发

0 前言 　　现在人民的生活日渐富裕,医疗技术更是日新月异,但患病的人数却不减反增。诸如癌症、糖尿病、高血压、脑溢血及心血管疾病等日益增多,有人称这个时代为“成人病的时代”。也有人甚至批评这个时代,是“全民亚健康时代”。 　　疾病原本是指不健康症状明显出现的情况,然而,就现在激增的成人病而言,从身体微恙到症状明显出现为止,仍有一段相当长的潜伏期。这种既非健康,又没有明显病痛的阶段,即称为“亚健康”状态。 　　酵素是生命体不可缺的物质,包括人类在内的所有生物,都必须由酵素的催化作用才得以生存。生命的构…     

糙米酵素发酵工艺的研究

含胚米糠富含多种生理活性物质，经发酵后又增添多种酶，可制成糙米酵素，作为功能性食品的基料，为人类提供新的营养途径。为探讨糙米酵素合适的发酵工艺条件，以保鲜米糠添加少量蜂蜜为底物，采用活性面包干酵母进行发酵试验。以还原糖消耗量作为试验指标，设计了包含酵母活化时间、发酵时间和接种量三个因素及三水平的正交试验，对发酵工艺条件进行了优化。试验结果表明：优化的工艺条件为酵母活化时间取1h，发酵时间为11h，接种量为1．2g酵母，20g米糠。每8g发酵样品中消耗的还原糖达13．682mg。     

糙米酵素淀粉酶合成动力学研究

以糙米为主要原料,添加麦芽、蜂蜜和食盐等辅料,接种酵母菌进行发酵生产糙米酵素,以淀粉酶活性为指标,利用Logistic模型确定了细胞生长的动力学方程、产酶动力学方程、基质消耗的动力学方程,并通过实验数据与动力学模型拟合图验证了各方程的准确性,本研究对糙米酵素的工厂化生产具有指导意义。      

糙米酵素的发酵工艺

以米糠、糙米为主要原料，配入适量蜂蜜、玉米胚油进行发酵，以功能活性物质——还原型谷胱甘肽为指标，通过正交试验确定糙米酵素发酵培养基的最佳配方和最佳发酵条件。     

糙米酵素淀粉酶合成动力学研究

以糙米为主要原料,添加麦芽、蜂蜜和食盐等辅料,接种酵母菌进行发酵生产糙米酵素,以淀粉酶活性为指标,利用Logistic模型确定了细胞生长的动力学方程、产酶动力学方程、基质消耗的动力学方程,并通过实验数据与动力学模型拟合图验证了各方程的准确性,本研究对糙米酵素的工厂化生产具有指导意义。     

糙米酵素及其产品开发

简述糙米酵素的生化原理、生理活性、加工与利用方法，同时介绍两种一步法加工糙米酵素食品的方法。     

糙米酵素发酵工艺的中试研究

为进一步优化糙米酵素的中试发酵工艺参数,以淀粉酶活力为测定指标,通过正交试验确定糙米酵素的中试发酵条件。结果表明,每100 kg原料,酵母接种量4%,发酵时间6h,发酵温度30℃。该条件下糙米酵素的淀粉酶活力稳定,平均值为442.2U/g。产品呈乳白色,气味醇香,酸甜适口,状态均匀。验证试验结果表明该工艺条件稳定可行,重复性好,为糙米酵素的工业化生产奠定了基础。     

黄原胶流变学特性及其协效性研究

研究了不同浓度的黄原胶溶液的黏度变化以及剪切速率和时间对其流变学特性的影响,此外还对黄原胶与瓜尔豆胶、CMC、果胶的协效性进行了研究.研究结果表明,黄原胶溶液的黏度值随浓度的增加而逐渐增大,对其进行线性回归得方程y=157.8x-182.07,其相关系数达到0.9838.触变性的测定发现,在升速过程中黄原胶的表观黏度随剪切速率的增加而逐渐降低,而在降速过程中,表观黏度有一定的回升,具有很明显的假塑性,并且能够形成触变环,不同浓度黄原胶溶液的黏度值都是随剪切速率的增加而逐渐减小,这些现象表明,黄原胶溶液是一种正触变性流体.此外还发现,黄原胶和瓜尔豆胶具有一定的协效性,当黄原胶同瓜尔豆胶的比例为9 ∶ 1时,表观黏度值达到最大,为768.2mPa.s.黄原胶与CMC、果胶无协效性.     

糙米酵素混菌发酵工艺优化

为促进混合发酵的糙米酵素中酿酒酵母和植物乳杆菌快速生长,以活菌数为指标对传统糙米酵素发酵培养基组分进行优化,并研究各因素之间的交互作用。由预试验确定各组分适宜浓度范围后通过Plackett-Burman试验得出3个重要影响因子:蜂蜜、糙米和NaCl。根据3个重要影响因子的效应大小设定最陡爬坡试验的方向和步长,采用Box-Behnken试验设计3因素3水平的响应面分析试验。优化后的混菌最佳发酵培养基的组成成分为蜂蜜3.38g/100 mL、糙米10.71g/100mL、NaCl 0.24g/100mL、小麦芽0.25g/100mL、大麦芽0.50g/100 mL、(NH_4)_2SO_40.50g/100 mL和茶叶粉0.025g/100mL。采用以上最佳发酵培养基进行验证实验得出活菌数为5.35×10~7 CFU/mL,是基础糙米酵素培养基活菌数(5.71×10~6 CFU/mL)的9.37倍。验证实验说明响应面法优化得到的函数模型与实际数据较为拟合。     

不同发酵条件对糙米酵素中活性成分的影响

发芽糙米酵素是以发芽糙米为主要原料,经酵母发酵制成的功能性食品。发芽糙米酵素中含γ-氨基丁酸、谷胱甘肽、γ-谷维醇等多种生理功能活性成分。本试验研究了蜂蜜添加量、酵母活化液添加量、发酵时间和发酵温度等因素对产品中谷胱甘肽、γ-氨基丁酸与淀粉酶活力的影响,并以γ-氨基丁酸含量为评价指标,通过Plackett-Burman试验设计方法对其生产工艺进一步优化。结果表明：当蜂蜜添加量为8%,发酵温度为30 ℃,时间为3.9 h,酵母活化液添加量为13%时,γ-氨基丁酸的含量最高为0.80 mg/mL。     

发芽糙米粉理化性质研究

对发芽粳糙米粉和发芽籼糙米粉基本成分、微观结构、热焓特性及糊化性质(RVA)等进行了研究。结果表明:与糙米粉相比,发芽糙米粉中粗脂肪含量降低,蛋白质含量增加,总淀粉含量降低,粗纤维、灰分等含量变化不明显;随着发芽时间的增长,糙米粉峰值粘度、最低粘度、崩解值、最终粘度和回升值都降低;发芽糙米粉峰值温度、起始温度、终止温度及焓值均比糙米粉低,且籼糙米高于粳糙米。扫描电镜结果显示:发芽后糙米粉颗粒结构变得较疏松,棱角不太明显,发芽籼糙米粉颗粒结构较发芽粳糙米粉颗粒结构更加疏松,淀粉颗粒体积更小。      

Relationship between the thermal conductivity and rheological behavior of acerola pulp: Effect of concentration and temperature

This study aimed to evaluate the thermal conductivity and rheological behavior of acerola pulp at concentrations of 5.5, 7.5, 9.5, 11.5 and 13.5 °Brix and temperatures of 20, 30, 40, 50 and 60 °C. Among the models used to determine conductivity, Maxwell-Eucken was used for data acquisition. Linear equations were fitted to evaluate the influences of concentration and temperature on the thermal conductivity of the pulp. The pulp structure, particle sizes and relation between insoluble and soluble solids were also discussed. The rheological behavior, specifically apparent viscosity versus shear rate, was influenced by both the soluble solids content and the temperature. Among the mathematical models used to test the fit of the experimental data, the Herschel–Bulkley model provided the best statistical adjustments and was then used to determine the rheological parameters. Apparent viscosity was correlated with temperature by the Arrhenius equation. Acerola pulps were shear thinning and thermal conductivity increases with viscosity decreasing with increasing temperature. The structures and concentrations had an impact upon the effective thermal conductivity. The temperature and concentration values have been fixed and equation expressing conductivity as a function of apparent viscosity was proposed, which enable the evaluation of an existing relationship between the two properties.     

食用沙蒿籽胶流变学特性研究

应用转筒式旋转粘度计，对沙蒿籽溶胀机械分离法制备沙蒿胶的流变学特性进行了研究，发现在浓度1%-1.75%之间胶液为时间相关性假塑性流体，在浓度0.5%为时间无磁的假塑性流体，沙蒿胶表观粘度随浓度增大而迅速增大，沙蒿胶的表观粘度不受pH的影响，在重复高速剪切和25-85℃范围内表观粘度无明显变化，沙蒿籽胶是一种重要的新型天然食品添加剂。     

Effect of temperature on rheological characteristics of molasses: Modeling of apparent viscosity using Adaptive Neuro - Fuzzy Inference System (ANFIS)

In this study, the effect of temperature on the rheological characteristics of apricot and date molasses was studied separately. Rheological characteristics of both molasses were evaluated in the shear rate range of 0.1-100 s⁻¹ at different temperatures (10-40 °C). Power law model was used for the calculation of flow behavior index and consistency coefficients of molasses. Consistency coefficients of apricot and date molasses were in the range of 5.408-39.905 Pa sⁿ and 0.910-2.852 Pa sⁿ, respectively. Molasses samples showed a non-Newtonian flow behavior. The effect of temperature on apparent viscosity was described by Arrhenius equation and calculated activation energy at the shear rate of 54.2 s⁻¹ was 41.42 and 38.19 kJ/mol for apricot and date molasses, respectively. An efficient predictive model for apparent viscosity values of molasses was constructed using Adaptive Neuro - Fuzzy Inference System (ANFIS) and this model showed satisfactory prediction with high coefficient of determination (0.979-0.999) and low root mean squared error (0.12-0.46).     

不同品种糙米粉糊化特性比较研究

以5种直链淀粉含量差异较大的糙米粉为原料,以水合特性、糊化黏度特性和热特性为分析指标,研究比较它们糊化性质的差异性,为加工糙米制品选取原料提供基础。结果表明,不同直链淀粉含量的糙米粉糊化性质差异较大,直链淀粉含量越高,其糙米粉吸水指数、水溶性及膨胀势越低,糙米粉糊化所需能量越多,粘度和回生值越低,衰减值越小,糊化所需时间差异不大。     

Influence of calcium fortification on sensory, physical and rheological characteristics of fruit yogurt

There has been great demand of calcium fortified dairy products as they can serve as an ideal vehicle for carrying extra calcium to fulfill the nutritional needs but there is need to generate information on the effect of fortification of calcium on the physical properties of these products. In the present study, the calcium enriched mango yogurt was prepared after fortification of pasteurized yogurt mix with 50 mg Ca/100 ml of calcium lactate, this level selected from a preliminary study of sensory evaluation. Fortification of yogurt with calcium lactate at this level significantly (P<0.005) increased the water holding capacity (WHC) by 2.99% on 1st day of storage. WHC of calcium fortified fruit yogurt was higher than control fruit yogurt on 7th and 14th day of storage. Measurements performed on slowly stirred samples (flow curves and final apparent viscosity) showed that calcium-enriched fruit yogurt had stronger structures. Calcium fortified fruit yogurt showed less shear thinning behavior as compared to control. Also, apparent viscosity measurements at constant shear rate showed a significantly (P<0.05) less decrease in initial apparent viscosity in calcium fortified fruit yogurt. However, no statistically significant (P>0.05) difference was observed in tan δ values of control and calcium fortified fruit yogurt indicating similar nature of bonds involved in the gel structure formation of both the yogurt samples. The more firm structure of the calcium fortified fruit yogurt is thus attributed to the higher extent of colloidal calcium phosphate cross-linking between casein micelles due to increased calcium content by fortification. Also flavor, color, and body and texture scores of control and calcium fortified fruit yogurt did not show any significant difference (P>0.05).     

糙米酵素红曲酒发酵工艺的研究

通过单因素试验和正交试验确定了糙米酵素红曲酒的发酵工艺模型及工艺参数,分析成品酒卫生指标、感官指标、理化指标及主要功能性营养成分,开发出一种风味、色泽、功能性均上乘的饮品。通过实验最终得出:糙米酵素红曲酒的最适原料配比(大米∶糙米酵素)为3∶1,以大米和糙米酵素为100%计,最适红曲添加量为10%,最适酵母加入量为1.0%,最佳原料与水的比例为1∶1.5,发酵温度控制在24～28℃,发酵8d。     

焙炒糙米理化性质的研究

对焙炒前后糙米的糊化度、brabender黏度、颗粒表面结构等理化性质进行研究,采用气相色谱-质谱(GC-MS)联用技术对糙米焙炒前后的挥发性香味物质进行比较,得出糙米在焙炒前后的糊化性质有大的改变,糙米经焙炒后香味物质明显增加。