酶制剂在肉类嫩化增味中的作用及提取方法

肉嫩、肉香是肉制品加工过程中追求的目标,如何来嫩化、增香,本文主要介绍酶制剂在肉品加工中对肉类嫩化增味的几种方法。同时介绍了酶制剂的几种提取方法。     

原位聚合法制备香精微胶囊的工艺优化研究

以低甲醚化蜜胺树脂为壁材,香精为芯材,采用原位聚合法制备了一系列香精微胶囊．通过对所制备的香精微胶囊进行显微观察、粒度分析、包裹率测试和稳定性考察,研究了工艺条件的影响,并对香精微胶囊的多层造壁效果进行了分析．结果表明,在搅拌速度为600r／min,壁材预聚体滴加时间为30min,50min缓慢升温至75℃保温固化的条件下所得到的香精微胶囊包覆效果良好,产品乳液稳定;双层壁材香精微胶囊的粒径分布最窄,而三层壁材的香精微胶囊具有最高的热稳定性,包裹率可达92．26％．     

日本大米食味理化学测定

大米食味的理化学测定，是对大米食味的科学分析和判定。本文从日本现有研究成果中，总结简述了日本有关大米食味理化学测定的测定指标和测定方法，并介绍了它们与感观性检查的相关性。     

Effectiveness of cardenolides as feeding deterrents toPeromyscus mice

I compared the feeding responses of five species ofPeromyscus mice (aztecus, polionotus, melanotis, leucopus, andmaniculatus) to three bitter-tasting cardenolides (ouabain, digoxin, and digitoxin) that differ greatly in lipophilic character.Peromyscus, like other muroid rodents, are unusual in that they can ingest relatively large amounts of cardenolides without adverse physiologic effects. In experiment 1, I determined avoidance thresholds for the three cardenolides with 48 hr, two-choice tests. Mice exhibited large interspecific differences in avoidance threshold, and the interspecific ranking of the thresholds (maniculatus=leucopus >melanotis >polionotus >aztecus) was the same for each of the cardenolides. In experiment 2, I reevaluated the avoidance thresholds, but this time monitored the pattern of intake (i.e., bout lengths) during initial feeding encounters with cardenolidelaced diets. For each cardenolide, mice were subjected to three tests. In test 1, they received a control diet; in test 2, a diet containing the cardenolide at a concentration 1 log, unit below the avoidance threshold (as determined in experiment 1); and in test 3, a diet containing the cardenolide at the avoidance threshold concentration. Results were similar across all species and cardenolide types: Bout lengths in tests 1 and 2 were statistically equal, whereas those in test 3 were significantly shorter than those in test 1. The rapid rejection of cardenolide-laced diets in test 3 is consistent with a preingestive (i.e., gustatory) mechanism underlying the avoidance thresholds. I conclude (1) thatPeromyscus species differ substantially in taste sensitivity to cardenolides and that these differences may influence each species' respective ability to eat cardenolide-laced insects; and (2) that a species' relative taste sensitivity to one cardenolide predicts its sensitivity to other cardenolides.     

Evaluation of the bitter taste in virgin olive oil

An analytical method has been developed to evaluate the intensity of the bitter taste in virgin olive oil. Results from the proposed method, based on extraction of the bitter constituents of virgin olive oil with methanol/water and measurement of the absorbance at 225 nm, show a significant correlation with the intensity of bitterness that had been evaluated in a sensorial manner by a panel. The developed method, therefore, offers a real alternative to the panel test for the evaluation of this attribute.     

Frying quality and stability of low-and ultra-low-linolenic acid soybean oils

To determine effects of very low levels of linolenic acid on frying stabilities of soybean oils, tests were conducted with 2% (low) linolenic acid soybean oil (LLSBO) and 0.8% (ultra-low) linolenic acid soybean oil (ULLSBO) in comparison with cottonseed oil (CSO). Potato chips were fried in the oils for a total of 25 h of oil use. No significant differences were found for either total polar compounds or FFA between samples of LLSBO and ULLSBO; however, CSO had significantly higher percentage of polar compounds and FFA than the soybean oils at all sampling times. Flavor evaluations of fresh and aged (1, 3, 5, and 7 wk at 25°C) potato chips showed some differences between potato chips fried in different oil types. Sensory panel judges reported that potato chips fried in ULLSBO and aged for 3 or 7 wk at 25°C had significantly lower intensities of fishy flavor than did potato chips fried in LLSBO with the same conditions. Potato chips fried in ULLSBO that had been used for 5 h and then aged 7 wk at 25°C had significantly better quality than did potato chips fried 5 h in LLSBO and aged under the same conditions. Hexanal was significantly higher in the 5-h LLSBO sample than in potato chips fried 5 h in ULLSBO. The decrease in linolenic acid from 2 to 0.8% in the oils improved flavor quality and oxidative stability of some of the potato chip samples.     

Effect of post-treatment microwave vacuum drying on the quality of 3D-printed mango juice gel

Abstract

This paper presents the development of three-dimensional (3D)-printed mango juice gel with microwave vacuum drying (MVD) post-treatment. In this study, the post-treatment MVD was used to improve the quality of the 3D-printed mango juice gel. The flavor, texture, water status distribution, and dielectric properties of products with different drying times (0, 2, and 4?min) were compared. We found that 3D printed products under a post-treatment of 4?min of MVD had the best shape retention and shape accuracy. 3D-printed mango juice gel under 4?min of MVD post-treatment exhibited a compact gel system with the highest ratio of bound water, as well as the highest hardness (445.19?g) and gumminess (89.11), and the lowest the relative dielectric constant (26.40) and dielectric dissipation factor (14.74). Also, samples evaluated under different drying times could be distinguished by comparing the responding signals of the e-nose. Based on these results, it was concluded that the MVD method is a promising way to improve the quality of 3D printed food.     

L-苯丙氨酸参与的Amadori化合物的合成及其在卷烟中的应用

研究了L-苯丙氨酸参与的Amadori化合物的合成反应条件,及该产物对卷烟吸味的影响。结果表明,用乙醇、丙二醇作溶剂,D-木糖或D-果糖作反应物,反应物配比为1∶3所得的Amadori产物对烟草的作用效果较明显。利用裂解-气/质联用仪（PYROLYSIS-GC/MS）测定了L-苯丙氨酸与木糖反应生成的Amadori化合物在300℃下裂解产生的多种致香成分,证实了L-苯丙氨酸与还原糖生成的Amadori化合物能改善卷烟制品的抽吸效果。     

2-甲基-2-乙酸乙酯基-1,3-氧硫杂环戊烷的合成

以活性炭固载硅钨酸作为催化剂,用乙酰乙酸乙酯与巯基乙醇缩和合成了具有浓郁苹果香气的香料化合物2-甲基-2-乙酸乙酯基-1,3-氧硫杂环戊烷(Ⅰ)。采用正交试验研究了影响目标化合物Ⅰ产率的主要因素,得到了优化反应条件：n(乙酰乙酸乙酯)：n(巯基乙醇)为1．1：1．0,催化剂固载量w(H4SiW12O40)=20％,m(催化剂)：m(巯基乙醇)为0．05：1,苯作带水剂,回流反应2h,目标化合物Ⅰ产率达90．5％。该催化剂重复使用10次仍具有较好的催化活性。     

气-质联用法检测韭菜中香味成分的研究

运用GC／MS条件,研究了韭叶石油醚提取物及氯仿提取物的化学成分,共发现10种含硫化合物,其中4种化合物首次从该植物中找到。其中主要香味成分为甲基硫代亚磺酸甲酯,通过仿生合成和探讨其波谱性质验证了其结构。