挤压膨化对大米粉糊化度及蛋白质体外消化率的影响

以大米粉为原料,采用挤压膨化法研究挤压膨化对大米粉糊化度及蛋白质体外消化率的影响,通过单因素及正交实验分析了物料含水量、螺杆转速、第五区温度对大米粉糊化度及蛋白质体外消化率的影响,分析得出挤压膨化大米粉的最佳参数为:物料含水量为18%,螺杆转速为190 r/min,第五区温度为190℃;在此实验条件下进行验证实验,糊化度为90.72%,蛋白质体外消化率为82.80%,挤压膨化后大米粉蛋白质体外消化率比未经挤压处理的大米粉蛋白质体外消化率提高了10.31%。本研究为大米精深加工提供一定的参考。     

热塑挤压蒸煮处理对鱼肉蛋白质消化率的影响

采用胃蛋白酶-胰酶复合处理法对几种热加工处理的鱼肉制品进行蛋白质体外消化率的测定,从蛋白质消化率角度,将热塑挤压蒸煮处理与3种传统热加工处理进行比较,了解几种热加工处理对鱼肉蛋白质营养价值的影响。研究结果发现,热塑挤压蒸煮处理方法比3种传统热加工处理方法更能提高鱼肉蛋白质的消化率,进而表明热塑挤压蒸煮处理方法比3种传统热加工处理方法有利于提高鱼肉蛋白质的营养价值。     

交联作用对蛋白类食品的影响

关于蛋白质交联作用对食品感官品质影响的研究已经得到了足够的重视,但是关于不同原因所导致的蛋白质交联作用对蛋白质消化率等方面的影响还缺乏系统性研究。本文综述了国内外近20 年来关于蛋白质冻融交联、酶促交联及热加工交联的机理,探讨了交联作用对蛋白质功能性质、蛋白质消化率及其对蛋白类食品品质的影响。     

高温储藏下小麦淀粉和蛋白质消化率变化规律研究

研究了40℃条件下人工加速陈化对小麦籽粒淀粉和蛋白质消化率的影响。结果表明,人工陈化12周的小麦籽粒中快消化淀粉(RDS)和抗性淀粉(RS)质量分数分别下降了30.15%和26.75%,慢消化淀粉(SDS)质量分数增加了26.59%,淀粉和蛋白质的消化率下降程度不同:淀粉水解20、50、80和120 min后消化率分别下降了30.15%、13.75%、7.06%和1.79%;胃蛋白酶处理的蛋白质消化率下降了8.27%,胃-胰蛋白酶处理的蛋白质消化率下降了4.91%,可溶性蛋白的提取率下降了34.29%。高温储藏对小麦淀粉和蛋白质的消化率影响显著(P0.05)。     

挤压参数对用于酱油生产的豆粕和面粉挤出物蛋白质消化率的影响

采用挤压技术对用于酱油生产的豆粕和面粉等原料进行预处理,可以使蛋白质适度变性,提高蛋白质消化率。本研究以面粉比例、物料含水率、挤压机套筒温度、模孔孔径、螺杆转速为五个试验因素,采用Box-Behnken中心组合设计试验,并采用SAS软件处理数据,分析挤压系统参数对蛋白质消化率的影响规律,得出最佳挤压工艺参数:面粉比例为13.0%;物料含水率为23.0%;套筒温度为135.0℃;模孔孔径为10.0mm;螺杆转速为200.0r/min,在此条件下蛋白质消化率为87.6%。与以蒸煮法处理原料的对照试验相比,蛋白质消化率提高了5.1%。     

霉变和辐照对大豆蛋白质理化性质和结构的影响

以新鲜大豆为原料制备了不同霉变程度的大豆,利用60Co-γ射线对大豆进行了辐照处理,采用胃蛋白酶体外消化率、氨基酸组分测定、SDS-PAGE电泳和傅里叶红外变换光谱(FT-IR)研究了霉变和辐照对大豆中蛋白质体外消化率以及蛋白质组成和结构的影响。研究表明:大豆培养30 d后,霉变导致大豆胃蛋白酶消化率降低23.74%,氨基酸总量减少2.07%,大豆蛋白质二级结构中的β-转角和无规卷曲分别增加了2.67%和4.17%,而α-螺旋和β-折叠相应减少3.62%和3.21%。在所考察的剂量范围内(10~30 k Gy),辐照对新鲜大豆的胃蛋白酶体外消化率、氨基酸组成、蛋白质亚基组成没有显著影响(P0.05),但对蛋白质二级结构中的α-螺旋与β-折叠具有显著影响(P0.05)。霉变大豆经过γ射线辐照处理后,氨基酸总量降低,蛋白质二级结构中的α-螺旋与β-折叠减少,无规则卷曲增加。     

鱼鳞过氧化处理后的蛋白质消化率测定

分别用过氧化氢和过乙酸对鲫鱼、草鱼、鲮鱼的鱼鳞进行预处理,再用体外消化法进行蛋白质胃蛋白酶消化率测定,比较了处理前后消化率的异同。结果发现,过乙酸和过氧化氢均对提高蛋白质胃蛋白酶消化率有明显的促进作用,提高最明显的为鲫鱼鳞,过氧化氢处理后的鲫鱼鳞消化率由原来的42.57%提高到75.62%,提高率为77.64%,过乙酸处理后的鲫鱼鳞消化率由原来的42.57%提高到64.10%,提高率为50.58%。     

不同热加工方法对羊肉制品体外模拟可消化性研究

以藏绵羊为研究对象,通过调控处理时间和温度进行微波、蒸制、炸制、煎制和煮制5种工艺处理,采用胃蛋白酶-胰蛋白酶体外模拟消化法测定了不同热加工方法的羊肉制品中蛋白质的体外消化率。结果表明:随着加热终点温度的增大,羊肉制品中蛋白质的体外消化率呈现先增大后降低的趋势。胃蛋白酶消化后,经微波、煎制、炸制加热处理的羊肉制品肉样中心温度为80℃时蛋白质消化率显著大于其50、60、70、90℃的蛋白质消化率(p﹤0.05),经蒸制和煮制加热处理的羊肉制品肉样中心温度为70℃时蛋白质消化率显著大于其50、60、80、90℃的蛋白质消化率(p﹤0.05),蒸制加热肉样至70℃时蛋白质消化率达到最大(65.58%±6.14%);经胃蛋白酶和胰蛋白酶两步消化后,5种加热处理的羊肉制品中蛋白质消化率与经胃蛋白酶消化的变化一致,蒸制加热肉样至70℃时蛋白质消化率达到最大(83.1%±4.74%)。该研究结果对人们合理选择羊肉的热加工方法以及工艺条件具有一定的指导意义。     

高粱蛋白质消化率研究进展

高粱不仅在半干旱热带发展中国家被作为主粮,且在发展中国家和发达国家也被作为动物饲料;高粱营养价值对于依靠高粱作为主要能量和蛋白质来源人们来说,是非常重要,而高粱必需氨基酸-赖氨酸含量低和蛋白质低消化率影响高粱营养价值。该文对高粱蛋白特征及其消化率研究进行综述。     

氨基酸的有效性对于蛋白消化率校正氨基酸评分的影响

蛋白质的传统化学评分是基于相关的氨基酸组成，蛋白消化率校正氨基酸评分综合了蛋白质的传统化学评分和氨基酸有效性的生物学评价。随着蛋白消化率校正氨基酸评分的产生，对于膳食蛋白品质的评价有了一个飞跃。本文重点研究测定蛋白中氨基酸有效性的问题，并讨了采用回肠消化率，粪便消化率，真消化率，实际消化率对于评价蛋白品质的不同影响。     

鸡内金炮制品对大豆分离蛋白体外消化特性的影响

该研究以鸡内金炮制品为原料,通过对消化率、酶活性、粒径大小以及相对分子质量分布的分析,比较不同方法制备的鸡内金炮制品对大豆分离蛋白体外消化特性的影响。结果表明：在不加外源酶时,鸡内金炮制品中的蛋白酶可能是引起蛋白质降解的主要原因。在加入外源蛋白酶时,添加鸡内金能提高大豆分离蛋白消化率,炮制品对蛋白质消化率的影响效果依次为：麸炒>醋炒>生品>砂炒>清炒,炮制品对蛋白质消化率的影响效果与其对酶活性的促进效果一致。麸炒和醋炒鸡内金在消化1 h时对蛋白质消化率的促进消化最显著,使大豆分离蛋白消化率由36.78%提高到41.33%和40.99%。体外消化表征结果也表明,添加鸡内金也会使蛋白质消化产物粒径减小、粒径分布的最大峰值左移、蛋白质相对分子质量分布向小分子范围偏移。鸡内金对消化产物的影响主要发生在消化前1 h内。该研究为鸡内金的深入研究提供新思路。     

体外模拟法测定婴儿奶粉中蛋白质的消化率

采用体外模拟的方法测定了婴儿奶粉中蛋白质的消化率。此法的重现性试验的相对标准偏差为1．73％，表明重现性较好。测定结果表明：各种不同原料间蛋白质的消化率差异显差。此法快速，简便，重现性好，可应用于婴儿食品质量的评定。     

Effects of baking on protein digestibility of organic spelt products determined by two in vitro digestion methods

Consumption of organic foods is steadily increasing because it is believed to be healthier than conventional foods. This study was designed to investigate protein digestibility of organic spelt bread, biscuit, cookie and muffin in comparison to their corresponding normal wheat products. Three types of fermented bread products namely, yeast leavened, sour and yeast/sour dough were evaluated. Protein digestibility was assessed based on two methods, three-enzyme one-step and two-enzyme two-step digestion in vitro. The one-step digestion method produced results that were comparable with in vivo (rat) methods whereas the two-step digestion method was more reliable in determining differences among the examined wheat products. Organic spelt used in the present study was comparable to common wheat in protein content averaging 15.4 g/100 g dry matter. Slight differences were observed between organic spelt and common wheat products in protein digestibility determined by the two digestion methods. However, significant differences were found among each wheat products. In general, after baking protein digestion was significantly increased. Spelt and common wheat bread products had similar protein digestibility within each type of bread with sour dough breads had the highest protein digestibility. Biscuit, cookie and muffin products possessed lower protein digestibility than breads. In general, variations in protein digestibility due to baking were more noticeable than that found between the two wheats.     

Can spectroscopy in combination with chemometrics replace minks in digestibility tests?

One of the most relevant but expensive methods of assessing the quality of fish meal is the physiological digestibility test with minks. The purpose of this study was to determine whether spectroscopic and chemical analyses evaluated with chemometrics can replace minks in digestibility tests. The spectroscopic methods used were the two complementary techniques of fluorescence emission and near‐infrared reflectance. The investigation included 54 samples of high‐quality fish meal ranging from 89.6 to 93.9 on the mink digestibility index. The investigation also included determination of seven quality parameters in the fish meal to substantiate the spectroscopic models on the mink digestibility. These quality parameters include the content of protein, oil, water, water‐soluble protein, ash and the biogenic substance cadaverine as well as the titration value. The study demonstrates that the mink digestibility could be predicted from combining the two reference quality parameters oil and ash with a correlation coefficient of 0.89. The best spectroscopic calibration models on the mink digestibility resulted in a correlation coefficient of 0.94 and a prediction error of 0.5 using the near‐infrared spectral ensemble and a correlation coefficient of 0.92 and a prediction error of 0.5 using the fluorescence spectral ensemble. In addition, the seven reference quality parameters could be predicted from the spectroscopic ensembles with good precision. © 2000 Society of Chemical Industry     

Protein quality evaluation of Amaranthus wholemeal flours and protein concentrates

Based on the amino acid composition, Amaranthus seed protein is known to be of higher quality than most of the major cereal grains. However, protein quality does not solely depend on amino acid profile but also on its digestibility. In this study we determined amino acid composition and in vitro protein digestibility of wholemeal and isoelectric protein concentrates (IPC) from five Amaranthus genotypes. Factors most likely to influence protein digestibility such as heating and presence of antinutrients were studied. Heating increased protein digestibility in wholemeals but slightly decreased it in IPCs. Trypsin inhibitor level was negatively but weakly correlated to protein digestibility, and the level of polyphenolic compounds was negatively and significantly correlated to protein digestibility. A slight deficiency in leucine was noted for wholemeals and in lysine for IPCs. However, based on both in vitro digestibility and amino acid profile, Amaranthus proteins were confirmed to be of better quality than those of other cereals. © 1998 SCI.     

Prediction of apparent heal protein digestibility in pigs with a two-step in-vitro method

The use of a two-step in-vitro method to predict the in-vivo ileal digestibility of proteins in pigs was investigated. It proved not possible to predict accurately the ileal protein digestibility with the in-vitro method. By dividing the samples into groups of closely related products, a good relationship (r² = 0.93) between in-vivo and in-vitro data was only obtained for wheat products, where only five samples were analysed. For beans, peas, rapeseed products and soya bean products it was still not possible to predict the in-vivo protein digestibility (r² = 0.03-0.60). The in vivo-in vitro relationship was mainly determined by the properties of the proteins and the presence of antinutritional factors, such as lectins and trypsin inhibitors. The first influences both the in-vitro and in-vivo protein degradability and the latter only reduces the in-vivo degradability by stimulating the secretion of endogenous protein. It is suggested that, with the in-vitro method, real ileal digestibility of proteins is predicted. The apparent ileal protein digestibility can only be predicted with the in-vitro method after making corrections for the influence of these antinutritional factors on the secretion of endogenous protein. Possibly corrections are also needed for microbial protein, and protein which is solubilised in the small intestine but not absorbed because of the physical state of the chyme.     

超声协同红枣多糖对功能性羊酸乳体外消化特性的影响

目的 探究超声协同红枣多糖对功能性羊酸乳体外消化特性的影响, 建立成年人和老年人模型, 并进行体外模拟胃肠道消化。方法 采用植物乳植杆菌(Lactiplantibacillus plantarum)JS19作为发酵剂, 并对羊酸乳进行超声处理和添加红枣多糖, 制备具有较高抗氧化活性的羊酸乳。为了进一步研究羊酸乳的特性, 通过测定不同处理组的植物乳植杆菌数、抗氧化活性、蛋白电泳、可溶性蛋白浓度、蛋白水解度以及蛋白消化率指标, 比较不同处理组消化处理前后各指标的差异。结果 超声协同红枣多糖能够显著提高羊酸乳的植物乳植杆菌数和抗氧化活性。同时, 蛋白电泳结果显示, 经过超声协同红枣多糖的羊酸乳蛋白消化度提高。此外, 经过处理的羊酸乳可溶性蛋白浓度、蛋白水解度以及蛋白消化率均有所提高, 表明超声和红枣多糖能够增加羊酸乳蛋白的可消化性。结论 本研究说明超声协同红枣多糖能够有效地提高羊酸乳制品的品质, 这一研究结果可能为羊乳开发利用和功能性乳制品的研发提供了有用的信息。     

In-vivo and in-vitro digestibility of starch in autoclaved pea and potato products

The digestibility of starch in homogenized/autoclaved pea plus potato products was studied in vitro and in vivo. The products were a canned infant purée based on peas and potatoes and products prepared in the laboratory by repeated autoclaving and cooling of either homogenized potatoes or homogenized peas. Small-intestinal digestibility was evaluated through balance experiments in rats treated with an antibiotic (Nebacitin) to supress microbial activity in the hind gut. Parallel experiments in normal rats were performed to study the fermentability of undigested starch. The small-intestinal digestibility was 93, 82 and 70% of tolal starch in the potato product, infant purée and pea product, respectively. Consequently, significant amounts of starch left the small intestine undigested, particularly with pea-based products. The major portion of the undigested starch consisted of a fraction which resisted amylases in vitro unless solubilized in alkali, ie retrograded amylose. The fermentability of starch reaching the hind gut was high, about 90%. In-vitro digestibility figures varied depending on the method used and were in the ranges 91–93, 76–86 and 71–77% in the potato product, infant purée and pea product, respectively. One of the methods allowed simultaneous and accurate determination of the in-vivo resistant retrograded amylose fraction.     

肉类蛋白质消化性影响因素研究进展

肉类中蛋白质含量丰富,且含有人体必需氨基酸,氨基酸比例接近满足人体组织生长和健康维持的需要。肉类营养价值主要通过蛋白质含量和必需氨基酸模式进行评估,而肉类蛋白消化性的相关研究却被较少关注。蛋白质的消化性受蛋白质来源、肌肉纤维类型、蛋白氧化程度及加工工艺等多种因素影响,提高肉类蛋白质的消化性对于人体生长和健康维持至关重要,同时还能预防部分疾病。本文主要从外部因素与内部因素两方面对影响肉类蛋白质消化性的因素进行系统性总结和归类,概述目前影响肉类蛋白质消化性因素的研究现状,以期为肉类蛋白的加工利用提供指导与帮助。