高压二氧化碳技术速冻香菇工艺

采用高压二氧化碳技术(high pressure carbon dioxide,HPCD)对香菇进行速冻,以期解决国内食用菌速冻技术存在的能耗大、成本高的问题。在原料热烫钝酶的基础上,通过单因素试验和正交试验,并结合速冻产品感官评价对工艺条件进行优化。结果表明:HPCD速冻香菇最佳工艺参数为处理釜初温6℃、处理釜设定压力7MPa、卸压时间4min,且卸压时间为影响速冻产品品质的最显著因素。     

速冻苹果片加工工艺研究

本文比较了浓度为0.5%的柠檬酸、0.005%的偏重亚硫酸钠、0.1%的抗坏血酸和0.9%的氯化钠溶液对苹果片的防褐变效果,并以速冻苹果片的食用品质和冻耗为依据,对其速冻工艺进行了优化,得到速冻苹果片的最佳制备工艺为:苹果片厚度为6mm,0.9%氯化钠溶液中浸泡5 min,速冻时的风速为6m/s.在此条件下得到的速冻苹果片的硬度适中,有甜的口感和苹果风味,口感评价得分16.86分(满分20分).     

速冻芦笋的热烫工艺条件研究

对速冻芦笋的热烫工艺条件进行了研究。结果显示，热烫因子笋径(A)、热烫温度(B)和热烫时间(C)对芦笋热烫效果影响的主次顺序为A＞B＞C；笋径对多酚氧化酶(PPO)和过氧化物酶(POD)活性有极显著的影响，对芦笋烫后的感官品质有显著影响；热烫温度和时间对POD活性有显著影响。芦笋热烫的适宜条件范围为茎粗0．8—1．4cm，热烫温度88—95℃，热烫时间为2—3min。热烫最佳处理组合为A2B3C1。     

高压二氧化碳保鲜双孢蘑菇的工艺优化

为了优化高压二氧化碳(high pressure carbon dioxide,HPCD)保鲜双孢蘑菇的工艺,在单因素实验基础上,采用响应面法分析HPCD处理压力、处理时间和处理温度对双孢蘑菇硬度和颜色的影响并对其进行优化。结果表明,HPCD保鲜双孢蘑菇的最佳工艺条件为:处理压力0.3 MPa,处理时间3 min,处理温度17℃;与对照相比,该条件HPCD处理后的双孢蘑菇可以更好的保持其硬度和颜色,低温贮藏8 d后的硬度为191.7 N(提高了18.85%),褐变指数(BI)为33.13(降低了16.80%)。因此,HPCD技术可以应用于双孢蘑菇的贮藏保鲜,具有良好的前景。      

咸酥花生加工中的浸渍工艺研究

盐水浸渍是咸酥花生加工中的一个重要工序,本文比较研究了盐水常压浸渍和真空浸渍对花生品质的影响,并应用正交试验优化盐水真空浸渍花生的工艺参数。结果表明:盐水真空浸渍的花生品质优于常压浸渍,在常压、浸渍温度25℃下,浸渍18 h的花生盐水吸收率仅为45.26%、可溶性蛋白质含量降低0.81%;而在真空度0.085 MPa、浸渍温度25℃下,浸渍1 min的花生盐水吸收率可达100%,且可溶性蛋白质含量仅降低0.02%。盐水真空浸渍花生的最佳工艺参数为真空度0.085 MPa、浸渍温度55℃、盐水浓度10%(W/W)、浸渍时间3 min,在该工艺参数下的咸酥花生的感官品质最佳。     

速冻菜肴红烧肉的工艺研究

为解决速冻菜肴红烧肉的工业化生产,采用正交试验,研究了速冻红烧肉的原料配方与加工工艺参数对速冻红烧肉品质的影响。试验结果表明,速冻红烧肉最优配方为料酒10％、糖色8％、米醋2％、老抽5％（以肉重计）;最佳工艺参数为肉块焯水时间2min、上色时间2min、焖焙时间2h,焖焙时间对速冻红烧肉感官评价影响显著。     

不同预处理对马铃薯片浸渍速率及感官品质的影响

采用理化测定和感官评定相结合的方法考察了烫漂、冷冻、微波干燥、烫漂+冷冻四种预处理方式对马铃薯片在麦芽糊精溶液中的浸渍速率及感官品质的影响。结果表明,以45%的糊精溶液为浸渍液,在45℃下进行浸渍,烫漂+冷冻的预处理方式浸渍速率最大,在30min时即已达最大浸渍量的80%,基本满足工艺要求;经此处理浸渍后的薯片外形平整饱满,色泽浅黄半透明,质感厚实。烫漂+冷冻的预处理方式可作为马铃薯脆片加工中浸渍工序的最佳预处理措施。     

不同预处理对马铃薯片浸渍速率及感官品质的影响

采用理化测定和感官评定相结合的方法考察了烫漂、冷冻、微波干燥、烫漂+冷冻四种预处理方式对马铃薯片在麦芽糊精溶液中的浸渍速率及感官品质的影响。结果表明,以45%的糊精溶液为浸渍液,在45℃下进行浸渍,烫漂+冷冻的预处理方式浸渍速率最大,在30min时即已达最大浸渍量的80%,基本满足工艺要求;经此处理浸渍后的薯片外形平整饱满,色泽浅黄半透明,质感厚实。烫漂+冷冻的预处理方式可作为马铃薯脆片加工中浸渍工序的最佳预处理措施。      

高压脉冲电场和热处理对蓝莓汁品质的影响

以蓝莓汁为原料,比较了高压脉冲电场(PEF)杀菌和热力杀菌处理对蓝莓汁中微生物和理化指标的影响,以及不同处理的蓝莓汁在贮藏期间的品质变化规律。结果表明:PEF可以有效杀灭蓝莓汁中的微生物;PEF杀菌对蓝莓汁色泽参数影响程度小;杀菌处理后,贮藏期内PEF处理和热处理对蓝莓汁的还原糖、总酸、可溶性固形物含量、总酚含量影响较小,PEF处理较热处理能更好地保持蓝莓汁中的VC和花青素含量。      

胡萝卜真空冷冻干燥工艺的研究

通过对胡萝卜进行真空冷冻干燥加工,经清洗,切分,热烫（90℃,1min）等预处理,预冻时间5h、预冻板温度-40℃,分时分段真空（真空度维持在5Pa左右）干燥,采用密封防潮包装,得到胡萝卜冻干产品。     

CO2浸渍时间对葡萄酒质量的影响

针对CO2不同浸渍时间对葡萄酒质量的影响进行了研究。结果表明:不同CO2浸渍时间对葡萄酒理化指标与感官质量都有明显影响;随着浸渍时间延长,酒的色度、香气浓郁度、pH值及挥发酸都明显增加,而总酸降低;室温条件下,浸渍240h的综合效果最好。     

超高压对鲜切胡萝卜硬度的影响及机制研究

鲜切果蔬的品质在加工后易受到破坏,超高压技术(high pressure processing,HPP)在鲜切果蔬品质保持方面具潜力。旨在探究鲜切果蔬的硬度随压力变化的规律及硬度变化的机制。本文以胡萝卜为对象,研究了超高压(100~600 MPa,5 min)对鲜切胡萝卜硬度、细胞膜完整性、果胶甲酯酶(pectin methylesterase,PME)及细胞壁果胶组成的影响。100 MPa处理后胡萝卜硬度无显著变化,随着压力增加,胡萝卜相对电导率显著增加,硬度显著下降,当达到300 MPa后,尽管压力继续升高,相对电导率和硬度变化已不显著;同时,高压处理后碱溶性果胶(sodium carbonate soluble pectin,NSP)增加,水溶性果胶(water soluble pectin,WSP)下降,但高压不能充分钝化果胶甲酯酶。超高压处理后细胞膜透性的改变和细胞壁果胶组分的变化共同影响了鲜切胡萝卜的硬度。      

超高压加工对鲜榨胡萝卜汁品质的影响

重点研究了热敏性胡萝卜汁经200～600MPa超高压处理10min后其感官品质、理化性质及营养品质的变化情况。实验结果表明:经高压处理后胡萝卜汁色泽、可溶性固形物、总糖、α-和β-胡萝卜素含量与对照样相比差异不明显(P>0.05);总抗氧化能力在400MPa压力处理后降低较显著,600MPa处理有较显著的提高(P<0.05);此外,超高压处理后胡萝卜汁的pH降低,总酸含量增加,且样品的沉降稳定性提高,且变化都比较显著(P<0.05)。综合实验各方面的处理效果,600MPa处理后的胡萝卜汁品质最佳。因此,超高压能较好保持胡萝卜汁原有的品质和营养价值,可达到保持营养、提高品质和延长货架期的目的。     

中低温蒸汽处理对鲜切胡萝卜片减菌效果及其品质的影响

以鲜切胡萝卜片为研究对象,采用中低温蒸汽(50～100℃)进行减菌处理,分析了蒸汽处理过程中鲜切胡萝卜片品质指标的变化。结果表明,鲜切胡萝卜片的菌落总数、水分、类胡萝卜素、硬度、色泽等指标均随处理温度及时间的增加而显著减少(P<0.05)。采用低温蒸汽(50～70℃)处理600s,对胡萝卜片的减菌效果明显,且失水率小于5%,类胡萝卜素保留高于85%,对蔬菜的硬度和色泽影响较小。而经中温蒸汽(80～100℃)及传统的沸水热烫处理后的胡萝卜片,其品质质地明显降低。因此,低温蒸汽减菌处理能有效降低胡萝卜片中的菌落总数,并可最大程度保护其品质质地。     

Changes in texture,microstructure and nutritional quality of carrot slices during blanching and freezing

Thermal processing of vegetables has pronounced effects on the cell structure, often lowering the final textural properties of the product. In order to investigate the effect of thermal processing on carrot, slices were subjected to different blanching and freezing treatments before frozen storage. Microwave-, steam- or water-blanched material was frozen and then stored at −24 °C. Steam-blanched carrots were subjected to blast freezing or cryogenic freezing at different temperatures before frozen storage. The influence of these process conditions on the texture (maximum load and slope), microstructure, dry matter, sugars, carotene and drip loss was investigated. Microwave blanching differed from the other blanching methods by resulting in a heterogenic cell structure. The content of dry matter, carotene and sucrose was higher following microwave blanching. Blast freezing resulted in low maximum load which seemed to be caused by major tissue damage. Concerning cryogenic freezing, lowering the temperature from −30 °C to −70 °C resulted in better preservation of the native microstructure together with an increase in maximum load, which was most pronounced after one month of storage. No significant effect was observed when lowering the temperature from −30 °C to −70 °C for any of the other measured parameters. © 1999 Society of Chemical Industry     

Effect of high hydrostatic pressure on quality parameters of lager beer

Unpasteurized lager beer samples from a commercial brewery were treated either by high hydrostatic pressure (HHP; 200, 250, 300, 350 MPa for 3 and 5 min at 20 °C) or by conventional heat pasteurization (60 °C for 15 min). The main attributes of the beer, such as ethanol content, extract and pH, were not affected by either treatment; however HHP and heat pasteurization affected colour, chill haze, protein sensitivity and bitterness. Change in bitterness was higher in conventional heat pasteurization, but pressures up to 300 MPa had no significant affect on bitterness. Although more studies should be carried out to investigate the effects of HHP treatment on different types of lagers and ales, our results revealed that HHP could be successfully used to process beer, even at temperatures well below those required for heat pasteurization, without affecting some of the quality attributes. Copyright © 2005 Society of Chemical Industry     

冰温真空干燥压力对猕猴桃切片干燥品质的影响

以去皮的猕猴桃切片为试材,利用冰温真空干燥技术对其进行脱水处理,研究不同干燥压力(150、350、550 Pa)对猕猴桃切片的干燥速率及干燥后品质的影响。结果表明,冰温真空干燥技术可以最大限度的降低营养物质的损失。干燥压力为350 Pa时的干制品品质最好,猕猴桃切片的失水率和糖度分别为70.6%和24.5%,而复水比、V_C含量、色差值分别为4.75、110 mg/(100 g)和20.35。表明冰温真空干燥技术具有良好的应用前景。      

Optimisation of freezing process with pressure steaming of potato tissues (cv Monalisa)

Response surface methodology (RSM) was used for determining optimum conditions of the freezing process on pectinesterase (PE) activity, rheological parameters and textural properties in potato tissues. In the process of production of frozen potatoes, the second step of the stepwise blanching prior to freezing was considered as a fixed factor and performed at 97 °C for 2 min as well as the freezing rate in the freezing step itself, which was carried out at −2 °C min⁻¹. The effects of variation in levels of temperature (57.93–72.07 °C) and time (15.86–44.14 min) in the first blanching step on the PE activity were studied using a central composite rotatable design. A Box–Behnken factorial design was used to investigate the effects of simultaneous variation of temperature (60–70 °C) and time (20–40 min) in the first blanching step and steaming temperature (112–122 °C) and time (1–3 min) on rheological parameters and textural properties. Blanching temperature was the independent variable that most influenced either enzymatic activity or rheological parameters. Stationary points showing maximum PE activity had critical temperature and time values of 64.22 °C and 29.37 min before freezing and 64.39 °C and 28.02 min after freezing and steaming of the tissues, and these values were very close to those obtained for some creep compliance parameters. Results show a high correlation between increases in PE activity and tissue firmness below optimum experimental freezing conditions, proving the role of the enzyme as one of the main contributors to the firmness which determines the textural quality of frozen potato tissues. © 1999 Society of Chemical Industry