Physicochemical Properties of Surimi Seafood as Affected by Electron Beam and Heat

Physicochemical changes of surimi seafood under electron beam (e‐beam) and heat were investigated. Heat caused color browning and texture softening. E‐beam (up to 4 kGy) deteriorated neither color nor texture when the sample temperatures were between 5 and 23°C. However, firmer texture was measured when samples were treated by e‐beam while frozen. None of the treatments changed rancidity of surimi seafood within the parameters tested. Heat, as compared with e‐beam, generated the same headspace volatiles, however, to a greater extent. E‐beam was determined to be an excellent pasteurization alternative for surimi seafood in terms of retention of fresh‐like physicochemical attributes.     

Influence of γ-irradiation and ice storage on fat oxidation in three Indian fish

The influence of low-dose γ-irradiation (up to 5 kGy) on fat oxidation in skin and flesh fractions of some commercially important fishes (Indian mackerel, white pomfret and seer) during ice storage was examined. Thiobarbituric acid (TBA) values increased in both control and irradiated fish particularly in mackerel and seer meat. In mackerel, the TBA values declined towards later part of storage. Pomfret skin, but not mackerel and seer skin, showed radiation-induced oxidation, which increased further during ice storage.     

Natural Products Inhibit Oxidative Rancidity in Salted Cooked Ground Fish

The extent of lipid oxidation in salted cooked ground fish treated with several natural products (polyphenols, dried spices and fresh spices) was measured by the production of thiobarbituric acid reactive sub-stances (TBARS). The fresh spices, ginger and tumeric, were more potent than garlic and onion (at 10% conc) in inhibiting lipid oxidation in salted cooked ground fish. The order of antioxidative potency of the dried spices was: cloves > cinnamon > cumin ～ black pepper > fennel ～ foenugreek. The dried spices were more effective antiox-idants than fresh spices. The polyphenols were the most potent group of natural antioxidants. The order of potency of the polyphenols (0.01% concentration) was: ellagic acid > tannic acid > myricetin > quercetin.     

咪草烟在不同pH值水溶液中稳定性的研究

采用高效液相色谱研究了咪草烟在ｐＨ９、８．５、８、７的蒸馏水、，冷开水，自来水溶液中的稳定性。结果表明：在室温条件下，咪草烟的分解率为自来水〉冷开水〉蒸馏水。在不同ｐＨ值水溶液中的分解率为ｐＨ９〉ｐＨ８．５〈〈ｐＨ７。在热贮扌，咪草烟分别在ｐＨ９、８．５、８、７的水溶液中的分解率为自来水３５．４１％、１５．６０％、９．１１％、１．３０％，冷开水３５．１０％、１４．７０％、９．１３％、１．００％，蒸     

去皮椒盐油炸花生货架寿命的研究

通过对去皮椒盐油炸花生的加速氧化试验，建立了计算其在任一贮藏温度下货架寿命的回归方程。此外，还对包装工艺和包装材料同货架寿命之间的关系作了探讨。     

Antioxidant activity of lipid-soluble phenolic diterpenes from rosemary

A high-performance liquid chromatography method for analyzing the phenolic diterpenes present in rosemary (Rosmarinus officinalis L.) and commercial rosemary extracts is reported. Carnosic acid was the major phenolic diterpene present in rosemary leaves, with lesser amounts of 12-methoxycarnosic acid and carnosol. Several commercial rosemary extracts also were analyzed by this method, and in addition to these three compounds other phenolic diterpenes, such as 7-methoxyrosmanol, 7-methoxy-epirosmanol, and rosmanol, were found in some samples. These latter three compounds seem to be artifacts, produced from carnosic acid by oxidation and cyclization. The major phenolic diterpenes were isolated, and their relative antioxidatn activities in soybean oil were measured by the Rancimat. The potency of carnosic acid was more than twice that of any other compound. The antioxidant activity of pure carnosic acid was compared to butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tertiary butylhydroquinone (TBHQ) and was several times greater than BHT and BHA but less than TBHQ. Nuclear magnetic resonance data for several of the compounds that were incompletely characterized in previous literature are reported.     

2-溴甲基-6-甲基萘和-2,6-二溴甲基萘的水解反应

探讨了 2溴甲基 6甲基萘 ( 2 bromomethyl 6methylnaphthalene:2 ,6BMMN)和 2 ,6二溴甲基萘 ( 2 ,6bis( bromomethyl) naphthalene:2 ,6BBMN)在几种条件下的水解反应。结果表明 :2 ,6BMMN的水解较容易进行 ,2 ,6BBMN的水解反应性很小 ;增大水溶液中碱的浓度和使用相转移催化剂 ( TEBAB)可以促进 2 ,6BBMN的产物的水解反应。     

Effects of herbs on hydrolytic and oxidative degradation of olive oil in canned tomatoes

The effects of adding mixtures of herbs such as garlic, laurel, and marjoram on selected chemical indices of olive oil from canned dried tomatoes were studied for various storage periods of up to 1 yr. Conventional analytical indices measured included acidity, PV, and p-anisidine value. Flavored samples showed kinetic constant values that were significantly (P=0.001) higher than unflavored ones, whereas oligopolymer and oxidized TG and DG contents were similar to or slightly higher than in the unflavored samples compared with those with herbs. The addition of the mixture of herbs slowed polymerization reactions but did not inhibit TG oxidation. Discrepancies between the results obtained by conventional analyses and high-performance size-exclusion chromatography indicated that the former approaches were insufficient to determine oxidative degradation of oil as a result of interferences from compounds in the food matrix.     

盐酸溶液中Fe3+的水解聚合边界条件

为了模拟Pu⁴⁺水解聚合行为，采用动态光散射法研究了盐酸溶液中Fe³⁺水解聚合边界条件，并采用热力学软件HSC Chemistry 6.0模拟计算了水解聚合过程中一些热力学函数值的变化。结果表明：在Fe³⁺发生水解聚合反应时，溶液中的c₀(H⁺)、c(Fe³⁺)和温度之间存在一定的关联性，提高Fe³⁺浓度和升高温度会促进Fe³⁺水解聚合反应；聚合胶体粒径随着Fe³⁺浓度和温度升高而分布越广，且测得中值粒径在100~1 000 nm。     

人常乳与牛常乳中全谱游离氨基酸和水解氨基酸的对比

以产后30～40 d的人常乳和牛常乳为原料,采用同位素标记相对和绝对定量结合高效液相色谱-串联质谱技术对人常乳和牛常乳中全谱游离氨基酸和水解氨基酸的种类及含量进行对比分析。结果表明,人常乳和牛常乳中游离氨基酸质量浓度分别为0.37 g/L和0.16 g/L,水解氨基酸质量浓度分别为2.5 g/L和3.3 g/L。在全谱游离氨基酸中,人常乳和牛常乳均检测到9 种必需氨基酸以及15 种非蛋白质编码氨基酸,分别检测到11 种和7 种非必需氨基酸,其中人常乳9 种必需氨基酸、10 种非必需氨基酸以及7 种非蛋白质编码氨基酸质量浓度显著高于牛常乳（P＜0.05）;在全谱水解氨基酸中,人常乳和牛常乳均检测到8 种必需氨基酸、10 种非必需氨基酸以及12 种非蛋白质编码氨基酸,其中人常乳γ-氨基丁酸、牛磺酸、α-氨基正丁酸和β-丙氨酸质量浓度显著高于牛常乳（P＜0.05）。本研究对比分析人常乳与牛常乳中全谱游离氨基酸和水解氨基酸的种类和含量差异,为配方乳制品以及功能性食品的发展提供一定的参考。