不同冻藏温度下镀冰衣处理对鲶鱼品质的影响

将鲶鱼样品分为镀冰衣组和对照组,以持水力、p H、挥发性盐基氮(TVB-N)、质地多面剖析(Texture Profile Analysis,TPA)为指标,研究鲶鱼在-18℃、-25℃冻藏90d内品质的变化规律。随着冻藏时间的增加,各组鲶鱼样品的p H、持水力、硬度、弹性都有不同程度的降低,TVB-N值逐渐升高;在相同处理条件下,样品在-25℃冻藏下比-18℃各指标变化幅度小;在相同冻藏温度下,镀冰衣组样品各指标变化幅度小于对照组;综合各项指标结果,冻藏温度对鲶鱼冻藏的品质有明显影响,镀冰衣处理能有效延缓鲶鱼的腐败变质,镀冰衣和降低冻藏温度联合运用能更好保持鲶鱼的品质。     

即食中华管鞭虾贮藏品质变化及其货架期研究

目的 探究贮藏期间,不同温度下(4、15、25和37℃)即食中华管鞭虾肌肉品质变化情况,并构建即食中华管鞭虾的货架期模型。方法 以即食中华管鞭虾为研究对象,测定不同温度下虾仁肌肉中挥发性盐基氮(total volatile basic nitrogen, TVB-N)含量、菌落总数、硫代巴比妥酸(thiobarbituric acid, TBA)值、色差、pH、持水力和感官评分变化,以虾仁肌肉TVB-N构建货架期模型。结果 随着贮藏时间的延长,不同温度下贮藏的即食中华管鞭虾肌肉TVB-N含量、菌落总数、TBA值和b*值均呈上升趋势;肌肉pH呈先下降后上升趋势;肌肉L*值和感官评分呈下降趋势,且贮藏温度越高,即食中华管鞭虾虾仁肌肉品质劣化越快。此外,受贮藏温度影响,4和15℃贮藏的虾仁肌肉持水力呈先上升后下降的趋势,而25和37℃贮藏虾仁肌肉持水力呈下降趋势。采用Pearson相关系数分析,确定了TVB-N含量和菌落总数为虾仁肌肉品质变化的关键性因子,其变化特征符合一级动力学模型。Arrhenius方程结果显示,虾仁TVB-N值的拟合精度更高,用TVB-N值建立货架期模型结果更为准确。通过模型验证发现,以虾仁肌肉TVB-N含量建立的货架期模型能够较为准确的预测其货架期。结论 贮藏温度升高会加速即食中华管鞭虾品质的劣化。4~37℃贮藏时,以虾仁肌肉TVB-N含量建立的货架期模型可较为准确地预测其货架期。     

中国对虾冻藏期间新鲜度和质构的变化

为研究加25%碎冰处理对熟制中国对虾冻藏期间新鲜度和质构的影响,检测-18℃冻藏期间中国对虾菌落总数、pH、TVB-N值、TBA值、硬度和弹性的变化。结果表明,蒸煮处理显著提高冻藏中国对虾的新鲜度指标(菌落总数、TVB-N值和TBA值; p0.05),加冰处理对熟制对虾的菌落总数没有显著影响(p0.05),但降低了熟制对虾pH上升幅度,加冰后对虾的TVB-N值和TBA值略有改善,且降低了贮藏后期(90～120 d)熟虾的硬度,并提高了弹性。加碎冰处理对中国对虾冻藏期间的新鲜度和质构有益。     

包装方式对养殖大黄鱼冻藏品质的影响

以养殖大黄鱼为研究对象,以感官特性、色差、持水力、质构、K值、挥发性盐基氮(Total volatile basic nitrogen,TVB-N值)、硫代巴比妥酸(Thiobarbituric acid value,TBA值)为评价指标,研究在冻藏120d镀冰衣、真空包装和无包装对养殖大黄鱼品质的影响。结果表明:随着冻藏时间的延长养殖大黄鱼的感官综合评分、质构、持水力均逐渐降低,3种包装处理下养殖大黄鱼TVB-N值,TBA值均随时间延长而增加,K值与TVB-N变化一致。与镀冰衣组和无包装组相比,真空包装下的养殖大黄鱼TVB-N值、TBA值和K值增加较缓慢。综合各指标变化,冻藏条件下真空包装有利于保持养殖大黄鱼较好新鲜度及冻藏品质。     

冰衣对冷冻南美白对虾贮藏品质的影响

通过测定－20 ℃冷冻条件下无冰衣组、15%镀冰衣组和25%镀冰衣组南美白对虾的感官评分、解冻损 失、蒸煮损失、挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、盐溶蛋白含量及肌苷酸（inosine-5’- monophosphate,IMP）关联物各比值,研究镀冰衣处理对冻藏南美白对虾品质的影响。通过分析IMP关联物各比值 （K、Ki、G、P、H及Fr）与主要鲜度指标间的相关性,探讨更适宜作为－20 ℃冷冻条件下镀冰衣南美白对虾品质评 价的指标。结果表明：随着贮藏时间的延长,3 组南美白对虾的解冻损失、蒸煮损失和TVB-N含量均呈明显上升趋势, 盐溶蛋白含量显著下降,25%镀冰衣组南美白对虾的品质始终优于无冰衣组和15%镀冰衣组;根据各指标间的Pearson相 关性分析,K、Ki、G、P、H及Fr值中,K值更适合用于评价该贮藏条件下南美白对虾的整体质量;无冰衣组、15%镀冰 衣组和25%镀冰衣组分别在贮藏第12、16、16周感官不可接受,镀冰衣能够有效延长冻藏南美白对虾的贮藏期。     

不同储存温度对中华草龟肌肉品质的影响

为研究不同储存温度对中华草龟肌肉品质的影响,以感官、pH、持水力、挥发性盐基氮(TVB-N)值、硬度和咀嚼性等为评价指标,研究中华草龟肌肉在-20、5、15、25 ℃储藏过程中品质的变化。结果表明:随着时间的推移,不同储存温度下中华草龟肌肉的持水力、硬度、咀嚼性等逐渐下降,TVB-N值升高,pH在25 ℃时先降后升,其它温度下逐渐下降;同一储存期,随着温度的升高,pH、持水力、硬度、咀嚼性等逐渐下降,TVB-N值升高;但是相对而言,储存时间对-20 ℃和5 ℃相关指标影响不显著(p>0.05),对15 ℃和25 ℃影响较显著(p<0.05)。根据分析结果,确定以TVB-N、pH、持水力为主要检测指标,以感官硬度、咀嚼性为参考指标,应用于中华草龟肌肉在储存过程中品质的监测。结果显示,较低储存温度能更好的保持中华草龟的肌肉品质。     

冷冻南美白对虾新型镀冰衣工艺优化研究

目的 优化冷冻南美白对虾(Penaeus vannamei)虾仁新型镀冰衣工艺。方法 采用单因素试验探究羧甲基纤维素钠(sodium carboxymethyl cellulose, CMC-Na)、海藻酸钠、高酰基结冷胶、低酰基结冷胶对南美白对虾的镀冰衣形成的影响,以及异抗坏血酸钠、柠檬酸和二氧化氯(ClO₂)添加量对南美白对虾保鲜效果的影响;利用响应面法对以异抗坏血酸、柠檬酸和ClO₂为原料的冷冻虾仁复合冰衣液进行优化。建立以菌落总数和白度为响应值的二次多项式回归模型,经方差分析和回归拟合,得到最佳复合冰衣液条件。结果 在镀冰衣过程中,与CMC-Na、海藻酸钠、高酰基结冷胶相比, 0.15%低酰基结冷胶形成冰衣量较为稳定,对冷冻虾仁的保护效果较好;异抗坏血酸钠、柠檬酸、ClO₂的添加量分别为0.8、0.4和0.04 g/L时,对冷冻虾仁的护色效果及杀菌效果最佳。冷冻虾仁最佳复合冰衣液条件为:柠檬酸、异抗坏血酸钠、ClO₂的添加量分别为0.40、0.75、0.04 g/L。结论 0.15%低酰基结冷胶可作为一种优良的添加剂应用于冷冻虾仁的镀冰衣中。合理配比的柠檬酸、异抗坏血酸钠、ClO₂复合冰衣液可以达到对冷冻虾仁抑菌和护色效果,保持虾仁品质。     

盐浓度对冷藏即食中华管鞭虾肌肉品质的影响

以中华管鞭虾为研究对象,探究NaCl浓度（0%、2%、4%和6%）对即食中华管鞭虾仁冷藏期间肌肉品质变化的影响。在冷藏0、10、20、30、40和50 d时,比较不同组别中华管鞭虾肌肉色差、质构特性、水分含量、持水力、pH、挥发性盐基氮含量（TVB-N）、菌落总数、TBA值及组织微观结构的变化情况。结果表明,在冷藏过程中,相比于0%NaCl处理组（对照组）,4%和6%NaCl可以显著（P<0.05）抑制虾仁肌肉色泽和质构特性的劣化,延缓肌肉TVB-N含量和TBA值的增加及微生物的快速生长。冷藏期间,各NaCl处理组虾仁肌肉持水力随贮藏时间延长而显著上升（P<0.05）,且NaCl浓度越高虾仁肌肉持水力保持效果越好。随冷藏时间延长,各组虾仁肌肉水分含量呈先上升后下降趋势,而肌肉pH则先下降后上升,但添加NaCl使得虾仁肌肉水分含量和p H均显著低于对照组（P<0.05）。冷藏第40 d时,与对照组相比,NaCl浓度增加抑制了虾仁肌纤维组织的劣化,其中以4%NaCl处理虾仁肌肉组织结构保持较为完整,肌纤维组织排列较为紧密。综上,选用4%NaCl浸泡处理可以改善保持中华管鞭...     

冻藏温度对罗氏沼虾冻藏品质的影响

以解冻汁液流失、蒸煮损失、TVB-N、K值、硬度、剪切力和色差为指标,研究不同冻藏温度对速冻罗氏沼虾冻藏品质的影响。试验结果表明:经液氮速冻后的罗氏沼虾,在-50,-18℃2种条件下冻藏,随着冻藏时间的延长,罗氏沼虾的持水能力和质构特性均变差,冻藏20周后,硬度分别下降了55.79%和59.45%。2种冻藏条件下的罗氏沼虾TVB-N和K值均随时间的延长而增加,而-50℃下冻藏的罗氏沼虾TVB-N和K值增加缓慢,说明较低的冻藏温度,有利于罗氏沼虾冻藏品质的保持。     

响应面法优化金枪鱼复合冰衣液配比

为了保持金枪鱼食用品质,延长货架期,利用Box-Behnend实验设计响应面法对金枪鱼复合冰衣液进行优化配比,并采用熵权法对持水力、色差和盐溶性蛋白含量计算总评分。建立了以总评分为响应值的二次多项式回归模型,经方差分析和回归拟合,得到复合冰衣液最佳配比质量分数:迷迭香酸0.3%,乳酸钠3.4%,竹叶抗氧化物0.12%。采用最佳配比复合冰衣液对金枪鱼进行镀冰衣处理,贮存6个月后测定持水力、蒸煮损失、盐溶性蛋白、挥发性盐基氮(total volatile basic nitrogen,TVB-N)等指标,对复合冰衣液保鲜效果进行验证。结果表明,相比于对照组,复合镀冰衣组能够抑制微生物生长,有效减缓TVB-N值增加,具有更好的持水力、盐溶性蛋白含量和色差值,有效保持金枪鱼的新鲜度。     

Freezing and Ice Recrystallization Properties of Sucrose Solutions Containing Ice Structuring Proteins from Cold-Acclimated Winter Wheat Grass Extract

ABSTRACT: The freezing properties of sucrose solutions containing ice structuring proteins (ISPs) from cold-acclimated winter wheat grass extract (AWWE) were evaluated. Neither significant ice nucleation nor thermal hysteresis activity in unpurified AWWE were detected ( P > 0.05). Ice recrystallization in sucrose solutions was assessed by bright field microscopy. Ice crystal growth was significantly reduced with the addition of more than 0.05% total protein from AWWE in 23% sucrose solutions frozen under static conditions and temperature cycled under long periods of time (60 min). Ice recrystallization inhibition was not evident when the samples were temperature cycled for shorter periods of time (10 min), indicating that an adsorption time may be required for the ISPs to be significantly active. The ice recrystallization was reduced with the increased on ISP concentration until reaching a plateau after adding 0.13% total protein from AWWE, representing a surface coverage of 9 mg protein/m² ice (assuming 100% adsorption). The reduction of ice crystal growth was as high as 74% compared with the control. This ice recrystallization inhibition offers significant opportunity for the use of ISPs from AWWE in frozen foods.     

结晶原理和冰淇淋中的结晶现象

阐述了结晶原理在冰淇淋凝冻中的应用,详细叙述了结晶的目的和方法,晶核的形成原理,结晶体的成长,多晶现象,以及冰淇淋中的结晶现象.     

黄单胞冰核活性细菌发酵制备的初步研究

应用正交设计与均匀设计对黄单胞冰核活性细菌的发酵制备条件进行了初步研究。结果表明 ,琥珀酸抑制了黄单胞菌生长与冰核活性的表达 ,甘油、蔗糖、乳糖、谷氨酸钠不同程度地促进了冰核活性和单胞菌的生长。较优培养基配方为酵母粉 1%、大豆蛋白胨 1%、MgSO4 ·7H2 O 0 0 5%、甘油 1%、蔗糖 2 %、乳糖 1%、谷氨酸钠 0 3% ,pH 7 0 ;较优发酵组合为细菌种龄 72h ,发酵时间 4 5h     

实验制作高淀粉冰淇淋

介绍了高淀粉冰淇淋的配方和工艺要点，并对实际制作过程中的操作要点进行了论述，为冰淇淋生产厂降低生产成本，寻找新的原料和食品添加剂提供了一种方法。     

Effect of biopolymers on structure and ice recrystallization in dynamically frozen ice cream model systems

Ice crystal growth and microstructure of sugarsolutions prepared with stabilizers (carboxymethyl cellulose [CMC], xanthan gum, locust bean gum [LBG], and gelatin) with or without milk solids-nonfat (MSNF) after freezing in a scraped surface heat exchanger and temperature cycling (5 cycles from -6 degrees C to -20 degrees C) were studied. Ice crystal growth was calculated from brightfield microscopic images acquired from samples before and after cycling. Freeze-substitution and low-temperature embedding (LR-Gold resin) were sample preparation techniques utilized for structure analyses by light microscopy and transmission electron microscopy. Differential staining for carbohydrates and proteins allowed the identification of stabilizer gel-like structures in LBG, gelatin, and gelatin/MSNF solutions. In the absence of milk proteins, xanthan and LBG were the most effective at retarding recrystallization, while in their presence, only xanthan had an effect. Cryo-gelation of the LBG was observed but is not the only mechanism of stabilizer action. Thermodynamic incompatibility between biopolymers was observed to promote localized high concentrations of milk proteins located at the ice crystal interface, probably exerting a water-holding action that significantly enhanced the stabilizer effect. Qualitatively, solution heterogeneity (phase separation) was directly proportional to ice crystal growth inhibition. It is suggested that water-holding by stabilizer and proteins, and in some cases steric hindrance induced by a stabilizer gel-like network, caused a reduction in the kinetics of the ice recrystallization phenomena and promoted mechanisms of melt-regrow instead of melt-diffuse-grow recrystallization, thus resulting in the preservation of the ice crystal size and in a small span of the ice crystal size distribution.     

Effect of storage temperature on quality of light and full-fat ice cream

Ice cream quality is dependent on many factors including storage temperature. Currently, the industry standard for ice cream storage is −28.9°C. Ice cream production costs may be decreased by increasing the temperature of the storage freezer, thus lowering energy costs. The first objective of this research was to evaluate the effect of 4 storage temperatures on the quality of commercial vanilla-flavored light and full-fat ice cream. Storage temperatures used were −45.6, −26.1, and −23.3°C for the 3 treatments and −28.9°C as the control or industry standard. Ice crystal sizes were analyzed by a cold-stage microscope and image analysis at 1, 19.5, and 39 wk of storage. Ice crystal size did not differ among the storage temperatures of light and full-fat ice creams at 19.5 or 39 wk. An increase in ice crystal size was observed between 19.5 and 39 wk for all storage temperatures except −45.6°C. Coldness intensity, iciness, creaminess, and storage/stale off-flavor of the light and full-fat ice creams were evaluated at 39 wk of storage. Sensory evaluation indicated no difference among the different storage temperatures for light and full-fat ice creams. In a second study, light and full-fat ice creams were heat shocked by storing at −28.9°C for 35 wk and then alternating between −23.3 and −12.2°C every 24 h for 4 wk. Heat-shocked ice creams were analyzed at 2 and 4 wk of storage for ice crystal size and were evaluated by the sensory panel. A difference in ice crystal size was observed for light and full-fat ice creams during heat-shock storage; however, sensory results indicated no differences. In summary, storage of light or full-fat vanilla-flavored ice creams at the temperatures used within this research did not affect quality of the ice creams. Therefore, ice cream manufacturers could conserve energy by increasing the temperature of freezers from −28.9 to −26.1°C. Because freezers will typically fluctuate from the set temperature, usage of −26.1°C allows for a safety factor, even though storage at −23.3°C did not affect ice cream quality.     

益生菌冰淇淋的开发

近年来我国食品工业中,冰淇淋成为继饮料、方便面后发展最为迅猛的产品之一。如何将冰淇淋的嗜好性与产品的营养和功能特性进行有机结合,是冰淇淋产品未来重要的发展趋势。本文从冰淇淋发展简史与近年市场状况,益生茵的种类和作用,益生菌冰淇淋的优势、研究与开发方向等方面进行了概述。     

高浓度臭氧冰制取技术的研究

用臭氧发生器制取高浓度臭氧气体,经高效涡旋气-水混合泵与水循环混合溶解臭氧而取得高浓度的臭氧水,然后把高浓度臭氧水持续地送入快速制冰机中制成鳞片状的臭氧冰。通过对影响制取臭氧冰浓度的臭氧气体流量、水温、混合压力、水pH和水质等条件进行研究,最终确定臭氧冰的生产工艺。实验结果表明,在水的pH为4.0,水温接近0℃,臭氧气体流量2.5L/min,混合泵出水压力0.2MPa的条件下进行循环混合,能制出高浓度的臭氧水和臭氧冰,所制得臭氧冰的臭氧浓度达16.7mg/L。     

Ice Recrystallization Inhibition in Ice Cream by Propylene Glycol Monostearate

ABSTRACT: The effectiveness of propylene glycol monostearate (PGMS) to inhibit ice recrystallization was evaluated in ice cream and frozen sucrose solutions. PGMS (0.3%) dramatically reduced ice crystal sizes in ice cream and in sucrose solutions frozen in a scraped‐surface freezer before and after heat shock, but had no effect in quiescently frozen solutions. PGMS showed limited emulsifier properties by promoting smaller fat globule size distributions and enhanced partial coalescence in the mix and ice cream, respectively, but at a much lower level compared to conventional ice cream emulsifier. Low temperature scanning electron microscopy revealed highly irregular crystal morphology in both ice cream and sucrose solutions frozen in a scraped‐surface freezer. There was strong evidence to suggest that PGMS directly interacts with ice crystals and interferes with normal surface propagation. Shear during freezing may be required for its distribution around the ice and sufficient surface coverage.     

冰核活性细菌发酵培养基的优化筛选

研究了不同营养构成及添加不同营养物质对冰核细菌生长和冰核活性的影响 ,采用正交试验优化了培养基组成。优化后的培养基最佳配方为 :在MPDA培养基中添加 0 4%半乳糖、1 5 %酵母粉、0 0 1%粗磷脂。在优化后的培养基中培养供试菌 ,菌体收获量 (干重 )比在MPDA培养基中培养增加 2 4g/L ,冰核活性增加 2 4 3 %。