啤酒非生物稳定性的研究进展

啤酒是一种稳定性不强的胶体溶液,在贮存或销售过程中极易产生混浊,严重影响了啤酒的非生物稳定性。首先对啤酒非生物混浊的种类进行了简单介绍,主要包括蛋白质类混浊、草酸钙混浊、β-葡聚糖混浊等;进而引出了提高啤酒非生物稳定性的措施,主要从原料选择、工艺控制、稳定剂添加及国内外新技术等方面进行了阐述,较系统的介绍了啤酒非生物稳定性的研究状况。     

麦汁煮沸与啤酒稳定性

本文论述了麦汁煮沸对啤酒非生物稳定性、啤酒生物稳定性、啤酒风味稳定性和泡沫稳定性的影响。     

酒稳定性的研究进展

总结了目前国内啤酒风味稳定性、非生物稳定性、生物稳定性方面的研究成果,对啤酒企业解决啤酒稳定性问题有一定的参考价值。     

啤酒缓冲性与质量稳定性关系的初步研究

选取了十几种市售啤酒 ,研究了啤酒缓冲容量与啤酒质量稳定性之间的相关性。同时有针对性地提出了增加啤酒缓冲容量的措施 ,并对酿造过程中磷酸盐的主要来源进行了研究。研究结果表明 ,啤酒缓冲容量与啤酒泡持、浊度稳定性和老化速度之间存在着线性相关性。增加麦汁或啤酒中总磷酸盐浓度既是提高啤酒缓冲容量的有效措施 ,又是减缓啤酒老化速度的重要手段之一。     

啤酒多酚物质对啤酒风味稳定性的影响

多酚是啤酒中重要的风味物质，对啤酒质量（非生物稳定性、风味稳定性以及口味）有着重要的影响。作者分析了啤酒中多酚物质的来源以及对啤酒风味稳定性的影响，并利用高效液相色谱测定了啤酒多酚中的单酚物质，研究发现其中的（＋）-儿茶素、（-）-表儿茶素、阿魏酸和槲皮素等单酚具有较高的抗氧化能力。     

啤酒胶体稳定性与泡沫质量

啤酒胶体稳定性与泡沫质量相互关联,又相互制约.啤酒中蛋白质组分极大影响着泡沫稳定性;而啤酒胶体稳定性很大程度上取决于啤酒中蛋白质组成及其络合物质.起泡蛋白、异葎草酮、二氧化碳是泡沫形成的三大要素;酒花加量、添加方法、煮沸强度对啤酒胶体稳定性及泡沫质量均有明显影响.为了提高啤酒胶体稳定性及泡沫质量的改善,在生产中应注意:①原料的选择,②掌握好生产工艺的控制要点.③采用单宁、蛋白酶、PVPP等稳定剂和还原剂处理,以改善啤酒胶体稳定性.(陶然)     

啤酒贮存过程中风味稳定性的研究

以青岛啤酒为样本,研究热力灭菌、贮存温度、溶解氧及添加氨基胍对啤酒风味稳定性的影响。结果表明,热力灭菌对啤酒的风味稳定性影响较小;贮存温度和溶解氧明显影响啤酒中5-羟甲基糠醛、B峰、史垂克醛类、TBN、DPPH还原力、色度等风味稳定性指标的浓度;啤酒中添加氨基胍能明显降低5-羟甲基糠醛、双乙酰、2,3-戊二酮等羰基化合物的含量,提高啤酒的风味稳定性。     

无添加甲醛酿造啤酒工艺的研究

啤酒酿造工艺中添加甲醛的问题已成为啤酒行业关注的热点.啤酒生产过程中添加甲醛主要解决成品酒的非生物稳定性,但是甲醛的添加严重破坏了啤酒风味稳定性.主要研究啤酒生产糖化过程中不添加甲醛,选择安全食品添加剂保证成品啤酒的非生物稳定性和风味稳定性.     

无添加甲醛酿造啤酒工艺的研究

啤酒酿造工艺中添加甲醛的问题已成为啤酒行业关注的热点。啤酒生产过程中添加甲醛主要解决成品酒的非生物稳定性,但是甲醛的添加严重破坏了啤酒风味稳定性。主要研究啤酒生产糖化过程中不添加甲醛,选择安全食品添加剂保证成品啤酒的非生物稳定性和风味稳定性。     

酵母自溶对啤酒质量的影响

1.前言酵母细胞质溶液中有多糖、氨基酸、多肽类、蛋白质、核酸、核苷酸、少量盐类等物质。酵母自溶酶可以降解细胞自身的蛋白质,生成一系列大、中、小分子的含氮化合物,这些物质大部分可以溶入啤酒中,从而改变啤酒中固形物的组成比例,导致啤酒的胶体稳定性和风味稳定性下降。本文主要就酵母自溶对啤酒胶体稳定性、风味稳定性的影响及防止酵母自溶的措施等方面进行了初步的探讨。     

天然VE油微胶囊的储存稳定性研究

以自制的天然V_E油微胶囊为研究对象,测定了其水分含量、流动性、粒径等指标,表征了其微观结构,研究了V_E油微胶囊的热稳定性、热水中的释放性以及光照、氧气、温度、相对湿度等环境条件对其储存稳定性的影响。结果表明:天然V_E油微胶囊的高温稳定性及在热水中的稳定性明显优于天然V_E油,其更适合在避光、密封隔氧、室温以下温度及干燥环境中储存。     

Aging and Processing Affect Color, Metmyoglobin Reductase and Oxygen Consumption of Beef Muscles

Color stability and various biochemical properties were determined in bovine longissimus dorsi and psoas major at different times postmortem (8 hr to 21 days) and during retail display. Surface metmyoglobin accumulation, metmyoglobin reductase activity and oxygen consumption rate were affected by muscle type, postmortem aging, and fabrication method (p < 0.01). Psoas steaks had greater metmyoglobin accumulation, lower metmyoglobin reductase activity, and greater oxygen consumption than longissimus steaks. However, color stability of muscles was similar after grinding, which increased oxygen consumption. Color was most stable in steaks fabricated at 4 or 7 days postmortem. The order of color stability was knife-cut steaks > saw-cut steaks > ground muscle.     

Effects of pyruvate on lipid oxidation and ground beef color

Our overall objective was to better understand the effects of added pyruvate on enhanced beef color stability. The 2 possible mechanisms assessed were the role of pyruvate in lipid oxidation and direct interaction between pyruvate and beef myoglobin. Microsomes were incubated with pyruvate at pH 5.6, 25 °C, and lipid oxidation was measured hourly for 3 h. Bovine oxymyoglobin at pH 5.6 was incubated with pyruvate and used to quantify both redox stability (metmyoglobin formation) and pyruvate-myoglobin adduction using mass spectrometry analysis. Surface color and lipid oxidation were measured on ground beef patties stored for 6 d in polyvinyl chloride over-wrap (PVC) or high oxygen. Addition of pyruvate to microsomes decreased lipid oxidation compared with controls (P < 0.05). Conversely, no effect on myoglobin was observed (no changes in redox stability and no peaks corresponding to pyruvate were observed; P > 0.05). However, pyruvate increased color stability and decreased lipid oxidation of ground beef patties packaged in PVC and high oxygen. Pyruvate decreased nitric oxide metmyoglobin-reducing capacity and oxygen consumption of patties compared with controls (P < 0.05). This research suggests that pyruvate may improve beef color stability primarily through its antioxidant effect on lipids. Practical Application: Discoloration of meat often results in significant revenue loss. This study suggests that pyruvate can improve the color stability of patties packaged in high oxygen and PVC primarily through its antioxidant effect on lipids.     

高氧气调包装肉类研究进展

肉类高氧气调包装通常是用含有70%~80%的氧和20%~30%的二氧化碳的混合气体对新鲜肉类进行包装的技术,其中的氧气可使肉类呈现稳定的红色,二氧化碳主要是抑制细菌的生长而延长贮藏期限。本文对近年来该技术在新鲜肉类中应用的研究情况进行了总结,从高氧包装对肉类颜色的影响、高氧环境下的微生物生长、高氧对肉类的脂类氧化和蛋白质氧化的影响以及提高高氧气调包装肉类品质的措施等方面进行了评述。肉类的颜色稳定性与肌肉类型有关,随O2浓度的增加而增大,随CO2浓度的增加而降低。另外,肉类颜色稳定性受肉类氧化特别是脂类氧化的影响。高氧气调包装肉类中的微生物受到CO2的抑制作用表现出比生长速率降低及生长的迟滞期延长。高氧气调包装会引起脂类和肌红蛋白的氧化以及蛋白质的交联,导致肉的嫩度和多汁性下降。高氧气调包装会导致肉类煮制时出现过早熟褐现象。添加某些防腐剂和抗氧化剂可以有效改善高氧气调包装肉类质量,延长肉类贮藏期限。     

蛹虫草黄色素A1稳定性研究

目的:研究了蛹虫草黄色素A1光稳定性、热稳定性、酸碱稳定性、金属离子稳定性及耐氧性,为开发蛹虫草保健食品提供参考依据。方法:采用高效液相色谱法(HPLC),以蛹虫草黄色素A1的保留率为指标,考察蛹虫草黄色素A1的稳定性。结果:影响蛹虫草黄色素A1光稳定性大小顺序为:太阳光>白炽灯光>紫外光>避光;低温下热稳定性良好,60℃以上不稳定;酸碱稳定性大小顺序为:酸性﹥中性﹥碱性;金属离子Na+、K+、Ca2+、Mg2+对其影响较小;氧气对蛹虫草黄色素A1的稳定性有一定影响。结论:蛹虫草黄色素A1提取纯化工艺应在避光、低温、绝氧及酸性环境下进行。     

Atmosphere and blooming time affect color and lipid stability of frozen beef from steers supplemented with Vitamin E

The influence of blooming time (1, 6 or 48 h) and atmosphere (air or 100% oxygen) on color and lipid stability of frozen Longissimus lumborum (LL) from control and vitamin E supplemented steers was studied. Samples were stored at -20°C with or without illumination. Blooming control LL for 48 h in air followed by dark storage increased discoloration. Supplementation and blooming in oxygen, separately or combined, increased color display life. Illumination increased discoloration. Supplementation coupled with blooming for 6 or 48 h in 100% oxygen provided the highest color stability in both dark and illuminated storage. Color display lives for supplemented LL bloomed for 6 and 48 h in oxygen were 182 and 212 days for dark storage, and 21 and 73 days for illuminated display. Supplementation decreased lipid oxidation in illuminated LL, but blooming for 48 h in oxygen minimized this effect.     

谈谈绍兴酒中的溶解氧

溶解氧在绍兴酒的酿造、贮存中也是一个重要工艺参数，但目前还未引起重视。就溶解氧对绍兴酒发酵、风味、稳定性、色泽等的影响进行了简要阐述，并对绍兴酒中溶解氧的来源及控制要点进行了分析。     

Biochemical factors influencing metmyoglobin formation on beef from muscles of differing colour stability

Biochemical parameters, such as oxygen consumption rate by muscle post mortem (OCR), depth of oxygen penetration into meat, rates of myoglobin oxygenation and deoxygenation and myoglobin content and succinic dehydrogenase activity, were determined for muscles of differing colour stability. Metmyoglobin reduction, in anoxia following oxidation with ferricyanide (MRA) and aerobically following oxidation with low pO(2) (ARA), were also determined. M. psoas major (poor colour stability) has higher enzymic activity than M. longissimus dorsi (good colour stability). This difference, together with the low myoglobin content in M. psoas major, results in relatively high OCR with consequent low oxygen penetration and rapid conversion of oxymyoglobin to myoglobin in M. psoas major, disposing it to rapid formation of metmyoglobin. Metmyoglobin reduction occurs both under anaerobic and aerobic conditions but no significant correlation is found between actual metmyoglobin reduction and rate of discoloration of different muscles. The most significant factor affecting colour stability of beef muscles appears to be their enzymic activity which determines the rate of myoglobin oxidation.     

Singlet Oxygen‐Related Photooxidative Stability and Antioxidant Changes of Diacylglycerol‐Rich Oil Derived from Mixture of Olive and Perilla Oil

Abstract: This study investigated the oxidative stability and antioxidants changes in diacylglycerol (DAG)‐rich oil under singlet oxygen. DAG‐rich oil was derived from triacylglycerol (TAG) oil of extra virgin olive and perilla oil mixture by hydrolysis and re‐esterification using lipases. The oxidation of oils was performed at 25 °C for 48 h under singlet oxygen produced with chlorophyll b under light, and was evaluated by headspace oxygen consumption and peroxide value (POV). The oxidation of DAG‐rich oil was higher and faster in the co‐presence of light and chlorophyll than in their single presence. DAG‐rich oil was more oxidation‐susceptible than TAG oil. There was no significant change in fatty acid and lipid subclass compositions in DAG‐rich oil during the photooxidation. Tocopherols were degraded, whereas polyphenols weren't during phootooxidation of DAG‐rich oil. The oxidation of DAG‐rich oil was well‐correlated with tocopherol contents, not with polyphenol contents, indicating that tocopherols were effective antioxidants in the singlet oxygen‐related phootooxidation of DAG‐rich oil. The results suggested that the oxidative stability of DAG‐rich oil under singlet oxygen be improved by a precise control through retention of tocopherols. Practical Application: The results of this study can be applied to the utilization of diacylglycerol oils to the area of functional edible oils with good oxidative stability.     

Biochemical factors influencing metmyoglobin formation in beef muscles

To explain the different rates of metmyoglobin accumulation in bovine muscles, biochemical factors such as oxygen consumption rate, cytochrome a(+a(3)) content, myoglobin autoxidation and enzymic ferrimyoglobin reduction were studied. The measurements involved five cows and five bulls. Only six cows were used for Metmyoglobin Reducing Activity (MRA) measurements. Three muscles with different colour stability (Tensor fasciae latae, Psoas major and Diaphragma medialis) were chosen. Meat colour stability, as well as the oxido-reduction potential of myoglobin, were highly related to muscle type. The animal effect was low or non-significant. Muscles with the poorest colour stability, such as Psoas major and Diaphragma medialis had the highest oxidative activities (oxygen consumption rate) and the highest myoglobin autoxidation rates. Enzymic ferrimyoglobin reduction, estimated either by spectrophotometric measurements from muscle homogenates in aerobic conditions ('Metmyoglobin Reductase Activity') or by reflectance measurements in anaerobic conditions (MRA), does not explain the differences observed in muscle colour stability.