Impact Of Long-Term Storage On The Instrumental Textural Properties Of Frozen Common Carp (Cyprinus Carpio,L.) Flesh

The aim of the work was to measure and confirm changes in the qualitative properties of frozen carp flesh (Cyprinus carpio L.) during 84 days of storage at -20°C, using instrumental texture profile analysis focused on hardness, cohesiveness, and springiness. Hardness in fresh fish was 2.908 N, in fish stored 28 days 1.238 N, after 56 days 0.505 N, and after 84 days 0.491 N. Cohesiveness (dimensionless unit) in fresh fish was 0.838, after 28 days 0.740, after 56 days 0.720, and after 84 days 0.712. Springiness (dimensionless unit) in fresh fish was 0.682, after 28 days 0.625, after 56 days 0.577, and at 84 days of storage 0.534. The texture profile analysis effect was determined by several regression and linear models. It is possible to calculate a certain time period in which changes develop up to the level of 50% of deterioration—in hardness 17.5 days and in cohesiveness 12.9 days, as this was proven to a defined significance level (P > 0.01). Only changes in springiness showed a linear regression in the level of 0.002 (rounded) for each day. Studies showed that the intensity of the most important changes in instrumental textural properties occurred during the initial 56 days after freezing and after up to 84 days of storage the changes continued at a lesser rate.     

Effect of Domestic Cooking Methods on Antioxidant Capacity of Fresh and Frozen Kale

The aim of this study was to evaluate the changes in the antioxidant capacity of fresh and frozen kale during domestic cooking methods (e.g., boiling, microwaving, and steaming). The antioxidant activities of the samples were measured using three in vitro assays (1,1-diphenyl-2-picrylhydrazyl assay, 2, 2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid assay, and ferric reducing antioxidant power assay). The steaming treatment was found to be the best cooking method to retain antioxidant compounds, followed by the microwaving and boiling treatments. The frozen uncooked samples exhibited a higher antioxidant capacity than the fresh, uncooked samples, indicating that the freezing process could enhance the antioxidant capacity of the kale.     

Antioxidant activity of pasteurized and sterilized commercial red orange juices

Blood orange juice is a typical Italian product whose red color is primarily associated with anthocyanin pigments. Two orange-based products are present on the market: pasteurized pure juice with 40 days of shelf life, and sterilized beverage containing minimum 12% of concentrated fruit juice. The aim of the present paper is to verify the relationships between the antioxidant properties and the anthocyanins content in a sampling of pasteurized and sterilized commercial red orange juices. The anthocyanins composition was determined by HPLC-MS/MS, while the antioxidant activity was evaluated by the Briggs-Rauscher reaction, selected in order to acquire information at acid pH values, by three radical scavenging assays (DMPD, 2-2'-azinobis-(3-ethylenbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), DPPH), and by FRAP assay to monitor the ferric reducing power. Results showed that antioxidant activity, particularly when measured by ABTS method, is positively related to the content of anthocyanins and that the reduction of anthocyanins content, typical of commercial long-shelf life juices, leads to a remarkable loss of antioxidant power.     

Fluctuations in the Levels of Antioxidant Compounds and Antioxidant Capacity of Ten Small Fruits During One Year of Frozen Storage

The fluctuations in antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl, 2,2´-azinobis (3-ethylbenzthiazoline-6-sulphonic acid), and ferric reducing/antioxidant power assays), total phenol, total flavonoid, and total anthocyanin contents of 10 small fruits (sweet cherries, sour cherries, strawberries, red currants, raspberries, blackberries, hawthorn, cornelian cherries, and red and white grapes) were monitored during storage at ?20°C. After one year in storage, all varieties except hawthorn and white grapes retained equal or slightly greater total phenol content in comparison to the initial values. The total flavonoid and total anthocyanin levels also remained stable or even increased after 12 months in all fruits exept hawthorn and strawberries. Red currants and raspberries exhibited optimal preservation of antioxidant capacity, while hawthorn showed a decrease in the antioxidant capacity during different time points in storage as well as at the end of storage. Analyzed fruits were classified into four main groups based on hierarchical cluster analysis.     

Effect of Processing and Storage on Antioxidant Capacity of Honey

ABSTRACT: The impact of heat and filtration on the antioxidant capacity of clover and buckwheat honey during storage was analyzed. Processing clover honey did not significantly impact antioxidant capacity (determined by oxygen radical absorbance capacity [ORAC] assay); processing lowered the antioxidant capacity of buckwheat honey (33.4%). The antioxidant capacity of honeys was reduced after 6 mo of storage with no impact of storage temperature or container type detected at the end point of the storage period. Processed and raw clover honey antioxidant capacity decreased about 30%. Processed buckwheat honey decreased 24% in antioxidant capacity, whereas raw buckwheat honey decreased 49%. Antioxidant capacity of processed and raw honeys was similar after storage. Phenolic profiles, peroxide accumulation, 5-(hydroxymethyl)-2-furaldehyde (HMF), gluconic acid, and total phenolics were also analyzed. The impact of storage on antioxidant components of processed and raw honey was complex.     

加工工艺对香榧油脂氧化和抗氧化活性的影响

研究了加工过程香榧酸价、碘价、过氧化值、p-茴香胺值、硫代巴比妥酸还原值和DPPH自由基清除能力的变化趋势,从而了解加工工艺对香榧油脂氧化和抗氧化活性的影响。结果表明,香榧在加工过程中发生了油脂的氧化酸败,其中第1次炒制和调味液浸泡后酸价和过氧化值分别较前道工序增加269.16%、56.07%和80.22%、73.17%;香榧抗氧化能力降低,表现为第1次炒制后硫代巴比妥酸还原值为前道工序的171.18%,而DPPH自由基清除能力下降至75.41%。因此,第1次炒制和调味液浸泡两道工序是影响香榧品质的重要环节。     

NaCl对冻藏期间冰全蛋功能性质的影响

为改善冰全蛋的功能性质,开发专用型冰全蛋产品,以鲜蛋为原料,研究了6 个月冻藏期内不同添加量NaCl（0.5%、1%、2%和4%）对冰全蛋功能性质的影响,并结合理化性质的变化对其原因进行分析。结果发现,冰全蛋表面疏水性随冻藏时间延长和NaCl添加量的增加而升高,而总巯基和表面巯基含量均随冻藏时间的延长而降低,但随NaCl添加量的增加呈现复杂变化。冰全蛋的溶解度随冻藏时间的延长而降低,添加1%和2%的NaCl冰全蛋的溶解度明显高于空白组;随冻藏时间的延长,冰全蛋的起泡性整体呈下降趋势,泡沫稳定性整体呈上升趋势,其中添加2%的NaCl可以显著改善冰全蛋的起泡性,60～180 d后起泡性仍优于未冻藏未加盐冰全蛋,且优于鲜蛋。同时,凝胶强度及凝胶持水性均在冻藏初期增加而后持续下降,添加1%的NaCl可以显著改善冰全蛋的凝胶性,30 d后凝胶性仍高于未冻藏未加盐冰全蛋,且高于鲜蛋。所以添加一定量的NaCl可改善冰全蛋的功能性质,为开发专用型冰全蛋的生产提供理论指导。     

冻固甜菜保藏与太阳辐射的关系

冻固甜菜的保藏效果受诸多气象因子的影响,其中太阳辐射的影响尤为明显。我们对甜菜冻藏堆表面太阳辐射能的分布特征进行了研究,列出了数学计算公式。根据呼和浩特糖厂的地理位置,冻藏到5月份以后,甜菜堆取东西堆向为好。随着保藏时间的推移,堆的南北侧面坡度越大越好,堆的东西侧面坡度相对越小越好。     

仙人草对低温蒸煮牛肉火腿储藏性影响

本文以市售牛肉火腿和不添加仙人草低温蒸煮牛肉火腿为对照,系统研究仙人草牛肉火腿储藏过程中细菌总数、腐败优势菌乳酸菌数、挥发性盐基氮(TVB-N值)、硫代巴比妥酸值(TBA值)、感官变化。结果表明:仙人草对牛肉火腿中细菌、乳酸菌、TVB-N值和TBA值有抑制效果。在4℃下,50天时市售牛肉火腿和不添加仙人草牛肉火腿出现轻微哈败味,57天时仙人草牛肉火腿仍未出现不良风味;不添加仙人草牛肉火腿和市售火腿储藏43天时TVB-N值分别为:21.0875和20.3973mg/100g,而仙人草牛肉火腿在57天才超过国标规定,为20.2225mg/100g,时间延长了14天。     

Effect of Frozen Storage and Other Processing Factors on the Quality of Surimi

A split plot design was applied to study the effect of frozen storage on the quality attributes of surimi. Gel strength of surimi products was shown to be significantly (P<0.01) affected by storage and its three-way or lower order interactions with leaching, grinding, setting and heating processes. Whiteness of the fish sausages was significantly (P<0.01) affected by storage and its interactions with leaching, grinding and heating processes. Significant interactions of storage with other process variables implies that the conventional single-variable-at-a-time strategy is inadequate to optimize the surimi processing system. Storage conditions should be included in optimization.     

决明子提取物的体外抗氧化实验研究

以决明子为原料，分别用乙酸乙酯、正丁醇和水制备粗提取物。利用自由基清除、还原力和抑制低密度脂蛋白氧化实验，对不同溶剂提取物的体外抗氧化特性进行研究。     

Effect of Processing on the Quality of Pineapple Juice

Pineapple processing plays an important role in juice preservation. Because the quality of the pineapple juice is affected by the processing technology applied, the effects of pasteurization and other preservation methods on the overall juice quality were discussed. During juice processing, microorganisms are destroyed and chemical changes occur. To optimize processing conditions, knowledge of the kinetics of these reactions is needed, but as of yet, data on the degradation of the amino acids and vitamin C and the change in sugar contents during pineapple juice pasteurization are scanty. Furthermore, the kinetics of hydroxymethylfurfural production should be investigated by a precise technique such as high-performance liquid chromatography.     

冻藏条件对人乳脂质及挥发性风味物质的影响

以新鲜人乳为对照(0d),设置-18、-60℃和-60℃快速冷冻(-60℃(Q))3种冻藏条件分别冻藏60 d与180 d,通过测定脂质含量、非酯化脂肪酸(non-esterified fatty acids,NEFA)含量、脂质过氧化物(lipid peroxide,LPO)含量、脂肪酸组成、乳脂肪球微观结构及挥发性...     

虾夷扇贝贝糜冻藏过程中部分理化性质的变化

研究虾夷扇贝贝糜在不同温度冻藏过程中(－18℃和－35℃)肌动球蛋白的盐溶性、Ca2+-ATPase和Ca2+-Mg2+-ATPase活性及活性巯基与总巯基含量的变化。结果显示：－18℃条件下冻藏5个月时,贝糜蛋白已严重变性,其各指标值分别降至新鲜样品的11.28%、20.31%、30.36%、68.49%和83.67%。－35℃条件下冻藏10个月时,相应指标分别降至新鲜样品的60.01%、45.25%、48.17%、82.80%和88.71%。两种冻藏温度条件下,贝糜的各个指标均随冻藏时间的延长而呈下降趋势,且－35℃冻藏时,各指标值相对于－18℃冻藏时下降幅度较小,表明－35℃冻藏效果优于－18℃冻藏。     

储藏温度对荔枝果汁中酚类物质含量及抗氧化能力的影响

以经UHT杀菌的荔枝果汁为原料,分析5周内在4、25、37℃3个储藏温度下荔枝果汁中总酚含量、总黄酮含量及FRAP和ABTS抗氧化能力的变化。结果显示,随着储藏时间的延长,在4、25、37℃储藏温度下荔枝果汁中总酚含量与抗氧化能力均呈现显著下降趋势(p<0.05);总酚含量受储藏时间影响更显著(p<0.05),总黄酮含量受温度影响更显著(p<0.05),抗氧化能力则同时受储藏时间(p<0.05)和温度(p<0.05)的影响。由此表明不同储藏条件对荔枝果汁中酚类物质含量存在显著影响,低温及短时储藏有利于保持荔枝果汁中酚类物质含量及其抗氧化活性。     

Antioxidant Effect of Korean Traditional Lotus Liquor (Yunyupju)

This study presented the antioxidant activities of the Korean traditional lotus liquor (Yunyupju) made from lotus blossom and leaves. The antioxidant activities are dose‐dependent and reached a plateau (about 80% inhibition) when the concentration of lotus liquor exceeded 25 μg in a modified linoleic acid peroxidation induced by haemoglobin. The concentrations to attain one absorbance unit at 700 nm were 23.6 ± 1.2 μg for Butylated hydroxytolene (BHT), and 45.7 ± 5.4 μg for lotus liquor. The scavenging activities of DPPH exerted by lotus liquor as well as α‐tocopherol were tested. Linear response curves were also obtained and the IC₅₀ were estimated as 5.6 μg for α‐tocopherol, 17.9 μg for lotus liquor. The maximum scavenging activity on hydroxyl radicals (40%) could be achieved when lotus liquor was more than 500 μg. Lotus liquor also has a potent superoxide radical scavenging activity, with value of 0.93 unit mg^?1 as superoxide dismutase equivalents. The IC₅₀ was estimated as 1.07 ± 0.04 mg for lotus liquor. The high performance liquid chromatography analysis of polyphenols was successfully achieved as these compounds appeared at 16.30 (catechin), 21.87 (rutin), 25.88 (unidentified peak), 31.51 (quercitrin), 35.19 (myricetin), and 36.72 (quercetin) min after injection of the sample, respectively.     

红花籽油的抗氧化功能研究

针对红花籽油的抗氧化功能进行研究,通过其对1,1-二苯基-2-三硝基苯肼自由基、超氧阴离子自由基、羟自由基的清除能力以及还原能力的测定,进行体外抗氧化试验;在体内抗氧化试验中,将60只雄性昆明种小鼠分为6组,其中阴性对照组和模型对照组给予蒸馏水,阳性对照组每日灌胃0.02 g/kg bw VE,3个试验组每日分别灌胃0.625、1.25、2.5 g/kg bw红花籽油,连续灌胃30 d。末次灌胃后,除阴性对照组外,模型对照组、阳性对照组和3个试验组均给予50%乙醇12 m L/kg bw造过氧化损伤,6 h后取样测定血清和肝脏中超氧化物歧化酶、谷胱甘肽过氧化物酶、还原型谷胱甘肽、丙二醛和蛋白质羰基的含量。结果表明:在体外抗氧化试验中,红花籽油对化学体系产生的自由基具有较强清除能力,同时还具有还原能力;在体内抗氧化试验中,红花籽油能显著提高血清和肝脏SOD、GSH-Px、GSH水平,降低MDA和PC含量,对乙醇所致机体过氧化性损伤起保护作用,以0.625 g/kg bw剂量效果最佳。结论:红花籽油具有抗氧化作用,但不能过量摄入。     

不同漂洗处理后冻藏对鲤鱼蛋白功能特性的影响

蛋白质氧化是引起食品加工及贮藏过程中品质发生劣变的一个主要原因。本文以鲤鱼肉为研究对象,主要研究鱼糜加工过程中经不同漂洗处理后冻藏对鲤鱼肌原纤维蛋白功能特性的影响。把鱼肉经不同方式漂洗[未漂洗;传统漂洗;添加抗坏血酸钠漂洗;添加没食子酸丙酯(PG)漂洗]后置于-25℃,经不同时间(0、30、60、90、120 d)冷冻贮藏后,利用质构仪、电子显微镜、流变仪等设备对鲤鱼肌原纤维蛋白乳化性、凝胶性以及流变性等指标进行测定,结果表明冻藏过程中发生的蛋白质氧化会引起鲤鱼肌原纤维蛋白各项功能特性降低,在漂洗过程中加入PG处理的鱼肉功能特性改变最小,说明添加PG漂洗可以有效地抑制蛋白质氧化的发生,从而减少鲤鱼肌原纤维蛋白功能特性的改变。     

Effect of Storage on 5-Hydroxymethylfurfural (HMF) Formation and Color Change in Jams

In this study, the effects of storage temperature (10, 20, and 37°C) and time (0, 2, 4, and 6 months) on the HMF and color values in strawberry, cherry and apricot jams were studied. Results showed that the HMF and total color difference (ΔE) values of all jams were increased linearly with storage time and higher values were found at higher storage temperature. Kinetic model was applied to changes in HMF and ΔE. Changes in HMF and ΔE were explained using zero-order reaction kinetics and the dependence of the rate constant on temperature was described by the Arrhenius equation