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微生物对木质纤维素水解液中混合糖的利用能力以及微生物对木质纤维素水解液中发酵抑制物的耐受能力一直是木质纤维素利用的关键问题。Spathaspora passalidarum作为非常规酵母,具有天然共发酵木糖和葡萄糖的能力。采用2种通气策略进行混合糖以及含有抑制物的混合糖的发酵,以进一步提高该菌株发酵纤维素水解液的利用能力。以50 g/L混合糖[m(葡萄糖)∶m(木糖)=1∶1],在无水解抑制物添加时,发酵36 h结束,糖醇转化率为0.46 g/g;添加木质纤维素水解抑制物后,96 h发酵依然不能结束,糖醇转化率仅为0.09 g/g,木糖几乎不能被利用。采取氧化还原电位(oxidation-reduction potential, ORP)调控策略,在最优ORP设定值为-110 mV时,48 h发酵结束,糖醇转化率为0.47 g/g;恒定通气也可以促进添加水解抑制物混合糖的发酵过程,但效果比ORP调控策略差。将添加抑制物的混合糖培养基调节pH为3,灭菌,可以避免美拉德反应对发酵造成的不利影响,之后调节发酵培养基pH为5,发酵过程控制ORP为-110 mV,发酵时间仅需24 h,糖醇转化率... 相似文献
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众所周知,酒精发酵的过程就是酵母菌将可发酵性糖转化为酒精的过程,而酵母是一种微生物,它的生长、繁殖、代谢酒精等一切生命活动,都需要营养的支撑,必须好好对待,否则它就不好好工作,尤其对于浓醪发酵而言。 相似文献
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麦芽汁变为啤酒,必须在麦芽中含有适量的可发酵的糖,经酵母中酶的作用使之转变为乙醇和二氧化碳,同时形成发酵副产物,这种副产物对啤酒的香气、口味和口味的醇厚性以及泡沫性能都有明显的影响,发酵副产物的形成和分解与酵母的代谢过程有密切关系,因此掌握发酵技术必须了解麦芽汁成分与酵母代谢的因果,麦芽汁组成和酵母代谢与啤酒质量是密切相关的。口味良好的啤酒,必须经过正常而顺利的发酵。取得顺当的发酵,应该以质量良好的麦芽和适宜的糖化操作来保证,在适合的麦芽汁组成下,经过酵母的正常代谢过程, 相似文献
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Yasmine Boudida Mohammed Gagaoua Samira Becila Brigitte Picard Abdelghani Boudjellal Carlos H. Herrera-Mendez 《Critical reviews in food science and nutrition》2016,56(6):957-972
Since years, serine proteases and their inhibitors were an enigma to meat scientists. They were indeed considered to be extracellular and to play no role in postmortem muscle proteolysis. In the 1990's, we observed that protease inhibitors levels in muscles are a better predictor of meat tenderness than their target enzymes. From a practical point of view, we therefore choose to look for serine protease inhibitors rather than their target enzymes, i.e. serine proteases and the purpose of this report was to overview the findings obtained. Fractionation of a muscle crude extract by gel filtration revealed three major trypsin inhibitory fractions designed as F1 (Mr:50–70 kDa), F2 (Mr:40–60 kDa) and F3 (Mr:10–15kD) which were analyzed separately. Besides antithrombin III, an heparin dependent thrombin inhibitor, F1 and F2 comprised a large set of closely related trypsin inhibitors encoded by at least 8 genes bovSERPINA3-1 to A3-8 and able to inhibit also strongly initiator and effector caspases. They all belong to the serpin superfamily, known to form covalent complexes with their target enzymes, were located within muscle cells and found in all tissues and fluids examined irrespective of the animal species. Potential biological functions in living and postmortem muscle were proposed for all of them. In contrast to F1 and F2 which have been more extensively investigated only preliminary findings were provided for F3. Taken together, these results tend to ascertain the onset of apoptosis in postmortem muscle. However, the exact mechanisms driving the cell towards apoptosis and how apoptosis, an energy dependent process, can be completed postmortem remain still unclear. 相似文献
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海参中多糖含量丰富,占海参干质量6%以上,具有抗肿瘤、抗凝血、抗氧化及抗帕金森病等多种生物学活性,在保健食品和药品开发方面具有广阔的应用前景。海参多糖的结构特性如分子质量、硫酸化模式及硫酸基含量等对其生物学活性具有很大影响,因此研究海参多糖结构对揭示其生物学活性及作用机制具有重要意义。本文在介绍海参多糖结构特性的基础上,重点综述其生物学活性及作用机制,同时总结海参多糖结构对其生物学活性的影响,最后对海参多糖的发展前景进行展望,以期为海参多糖的精深加工和应用提供理论支持。 相似文献
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血管紧张素转化酶(angiotensin converting enzyme,ACE)抑制剂通过抑制ACE活性能够降低血压。目前人工合成ACE抑制药物已开发并应用到降血压的治疗中,但会带来多种副作用。食源性ACE抑制肽与合成抑制剂相比因其副作用小、安全性高等特点,成为ACE抑制肽研究的热点。由于独特的生活环境与巨大的存在数量,海洋生物具有与陆地生物截然不同的化学结构及丰富的生物活性成分。海洋生物来源ACE抑制肽的研究为食源性ACE抑制肽的筛选提供了基础。本文结合海洋生物来源ACE抑制肽的作用机制及制备流程,对鱼类、软体动物、虾类、藻类及海绵、海蜇、粗刺参等不同生物来源的ACE抑制肽制备工艺进行了综述,并对海洋生物的综合开发利用进行了概括。 相似文献
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植物多肽类胰蛋白酶抑制剂(Trypsin inhibitor,TI)作为一种丝氨酸蛋白酶抑制剂具有广泛的生物学活性,参与了降糖、抗癌、抗炎、抗病、抗虫等多方面的生物学过程,在食品科技、医学、农业等多个领域具有重要的用途。其中,对于TI降糖活性的研究,目前虽有学者进行了部分动物实验,但缺乏分子靶标以及分子机制研究,国内外对TI降糖作用机理的认识仍处于起步阶段。本文围绕胰蛋白酶抑制剂在降糖方面的作用及其研究进展进行了总结,重点分析了分子靶标是α-葡萄糖苷酶的降糖机制,并对胰蛋白酶抑制剂降糖功效的应用与开发提出了展望,为今后深入研究胰蛋白酶抑制剂的降糖机理提供理论参考。 相似文献
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金属-有机骨架材料(metal-organic frameworks,MOFs)具有比表面积大、热稳定性好、孔径尺寸可调控、孔大小分布均匀、表面修饰可调控等特性。简述了MOFs的研究概况,论述了其作为分离介质的优点,综述了近几年其在磷酸肽、抗生素、食品添加剂、食品农药残留、有机污染物等的分析和在气体吸附、传感器中的应用。在未来,利用MOFs得到的氧化物可作为色谱固定相,应用在色谱仪器中分析生物大分子,也可以制备具有磁性的MOFs,用于蛋白质的分离提取等,这表明MOFs在食品生物分析领域具有良好的应用前景。 相似文献
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饲料中的抗营养因子及其灭活 总被引:1,自引:0,他引:1
抗营养因子普遍存在于植物性饲料中,主要包括蛋白酶抑制因子,植物凝集素、非淀粉多糖、植酸、单宁、糖苷、游离棉酚、抗维生素因子、脲酶等,目前主要通过物理、化学和生物学方法对其进行灭活和钝化,对饲料中抗营养因子的种类、性质、抗营养机理及灭活方法作一综述。 相似文献
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禽蛋蛋白质具有多种功能和生物活性,是制备生物活性肽的潜在前体物质。众多研究已证实禽蛋源多肽是一类很有前景的保健食品和功能性食品成分,除含传统的营养价值之外,还因其众多的生物活性而广受青睐,如抗氧化、降血压、抗菌、抗病毒、抗癌、抗糖尿病、抗炎、金属离子结合与转运、免疫调节、改善骨骼健康等。本文综述了禽蛋源生物活性肽的制备、鉴定、功能活性及胃肠道消化吸收与转运方面的研究进展,并对后续的研究趋势和实际应用过程中所面临的问题进行了展望,以期为禽蛋源生物活性肽后续的深入研究与应用开发提供一定的参考。 相似文献
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The Maillard reaction, which is generally termed nonenzymatic browning or glycation, has been implicated in accelerated aging and diabetic complications in vivo. Although the molecular basis of glycation-induced pathogenesis is not well understood, the following have been noted: (1) protein glycation leads to the formation and accumulation of toxic advanced glycation endproducts (AGEs); (2) AGEs can permanently alter the structure and function of body proteins; and (3) the interaction between AGE-modified proteins and AGE-specific receptors (RAGEs) on the cell surface induces the overproduction of reactive oxygen species (ROSs) and inflammatory mediators, which leads to cellular disorders in biological systems. To date, studies that have examined the contribution of protein glycation to disease-states have primarily focused on the deleterious effects and related mechanisms of these glycotoxins. However, it remains unknown whether phytochemicals exert protective effects against glycotoxin-induced damage. Thus, the development and investigation of AGE inhibitors, especially the natural anti-AGE agents without adverse effects, may provide a therapeutic approach for delaying and preventing premature aging and diabetic complications. In this review, we provide an outline of anti-glycation properties of foodstuffs and/or their active components, and discuss their mechanisms of action. 相似文献