澄清型香蕉汁加工过程中酶褐变的抑制

使用可食性抑制剂控制澄清型香蕉汁加工过程中的酶褐变。结果表明,L-半胱氨酸、抗坏血酸、柠檬酸均能同时显著地抑制香蕉PPO和POD活性,在打浆时添加0.5%柠檬酸,在酶解结束后再添加0.025%L-半胱氨酸和0.05%抗坏血酸能有效地抑制香蕉汁的酶褐变。     

抑制剂对蓝莓果汁加工过程的酶促褐变研究

为了解决蓝莓果汁在加工中易引发严重的酶促褐变而影响其食用品质和营养价值的问题,研究了蓝莓果汁加工过程中关键加工单元中酶促褐变的情况,就抗坏血酸、柠檬酸、氯化钙及L-半胱氨酸对酶促褐变的抑制作用进行了研究。探讨复合抑制剂在不同贮藏时间、温度下对果汁褐变程度的影响。结果表明,蓝莓果汁中多数褐变发生在打浆过程,因此抑制剂应该在打浆时加入。单一抑制剂在其所选浓度范围内对蓝莓果汁加工过程中酶促褐变的抑制程度顺序为:L-半胱氨酸>氯化钙>抗坏血酸>柠檬酸。最佳的抑制剂组合为抗坏血酸为0.09%,柠檬酸为0.5%,氯化钙为0.1%,L-半胱氨酸为0.1%。复合抑制剂在25℃和37℃条件下可有效抑制果汁的酶促褐变,而4℃条件下的影响并不显著。该研究可为利用抑制剂控制蓝莓果汁褐变提供理论和参考依据。     

新型凉果褐变抑制剂的研制

为解决广式凉果中二氧化硫超标的问题,本研究以苹果切片和青梅作为模型,进行单一因素和复配试验,通过测定白度、吸光度并结合感官评价,研发出新型的抑制凉果褐变添加剂.结果表明:鲜切苹果片腌制1d的抑制褐变效果最为理想;1.25 mg/gL-半胱氨酸盐酸盐、2 mg/g异抗坏血酸、5 mg/g柠檬酸和0.625 mg/g亚硫酸氢钠对苹果片(腌制1d)褐变均有较好抑制效果;由感官评价可知,L-半胱氨酸盐酸盐的抑制凉果褐变效果强于亚硫酸氢钠;用异抗坏血酸、柠檬酸、L-半胱氨酸盐酸盐进行复配试验,得出最佳配方:1.25 mg/gL半胱氨酸盐酸盐、5mg/g柠檬酸、1mg/g异抗坏血酸.试验表明:L-半胱氨酸盐酸盐及其复配可用于抑制凉果褐变.     

抑制剂控制橄榄汁酶促褐变的研究

研究抑制剂PVPP、抗坏血酸、L-半胱氨酸对橄榄汁护色效果的影响,结果表明:在特定的环境条件下,一定浓度的PVPP、异抗坏血酸钠、L-半胱氨酸对橄榄多酚氧化酶酶促褐变均有较好的抑制效果,其中PVPP抑制效果最为明显,最佳条件是:PVPP浓度40mg/L,温度30℃,时间80min,pH为6。     

双孢菇干制的非硫护色剂研究

为解决双孢菇干制过程中的褐变问题,选用柠檬酸、氯化钙、氯化钠、抗坏血酸、乙二胺四乙酸二钠、L-半胱氨酸和六偏磷酸钠7种护色剂对双孢菇进行护色处理。单因素实验表明:不同护色剂对双孢菇褐变都有一定的抑制作用,其中氯化钙、抗坏血酸、L-半胱氨酸和六偏磷酸钠护色效果明显。通过响应面优化实验得出非硫复合护色剂的最佳组合为:抗坏血酸0.053%,L-半胱氨酸0.021%,六偏磷酸钠0.047%,氯化钙0.061%。该复合护色剂重复使用25次仍有很好的护色效果。     

正交试验法优化板栗蓉分级护色工艺

为抑制板栗在制蓉过程的褐变,对其加工过程采用二级护色工艺。通过测定样品的总色差(△E*),分别研究了柠檬酸、抗坏血酸、L-半胱氨酸和氯化钠对板栗色泽的影响,进行单因素和正交试验,确定最佳的护色液配方。结果表明,柠檬酸、抗坏血酸、L-半胱氨酸和氯化钠在板栗制蓉过程中均有抑制褐变的效果。一级护色的最佳配方为:柠檬酸0.05%,抗坏血酸0.75%,L-半胱氨酸0.17%,氯化钠2.00%;二级护色的最佳配方为:柠檬酸0.45%,抗坏血酸0.65%,L-半胱氨酸0.05%,氯化钠1.90%。     

鲜切梨褐变抑制的研究

研究了不同褐变抑制剂对鲜切梨褐变度、PPO活性、感官品质的影响.实验结果表明,单一使用1.0%柠檬酸、0.01%水杨酸、0.3% L-半胱氨酸处理均能较好的抑制鲜切梨褐变.但是采用0.3%L一半胱氨酸+0.01%水杨酸+1.2%柠檬酸,浸泡9min的复合处理效果最佳,可使鲜切梨的褐变度在12d内保持较优水平.     

红枣干制护色工艺研究

以骏枣为原料,以柠檬酸、草酸、抗坏血酸、L-半胱氨酸为护色液,研究浸泡时间、护色液浓度和浸泡温度对红枣褐变的影响。结果表明:柠檬酸最佳配比为浓度3%,温度50℃,时间40min,此时的褐变度为0.34;草酸最佳配比为浓度1%,温度50℃,时间30min,此时的褐变度为0.36;抗坏血酸最佳配比为浓度1%,温度60℃,时间40min,此时的褐变度为0.453;L-半胱氨酸最佳配比为浓度0.3%,温度60℃,时间20min,此时的褐变度为0.435。     

野木瓜果汁非酶褐变复配抑制剂的优化

为优化野木瓜果汁非酶褐变复配抑制剂配比,通过单因素试验,选择并确定EDTA-Na_2、D-异抗坏血酸钠、L-半胱氨酸、柠檬酸4种抑制剂及其水平,以褐变抑制率为响应变量,采用Box-Behnken设计响应面试验方案。利用Design Expert 8.0软件得到回归模型并进行响应面分析,确定野木瓜果汁非酶褐变复配抑制最优配比为:EDTA-Na_2 0.001 1%、D-异抗坏血酸钠0.212 6%、L-半胱氨酸0.543 4%、柠檬酸0.191 7%,该复配抑制剂的抑制率为77.14%。     

柠檬酸与五种褐变抑制剂的交互作用对马铃薯护色的影响

以鲜切马铃薯为护色对象,研究柠檬酸分别与五种褐变抑制剂(亚硫酸氢钠、L-半胱氨酸、苹果酸、抗坏血酸、氯化钠)在抑制鲜切马铃薯褐变上的交互作用。采用两因子两水平析因实验设计,结果以方差分析和交互作用效应图表示。结果表明:柠檬酸与氯化钠、抗坏血酸和L-半胱氨酸之间有极显著的交互作用,且柠檬酸对氯化钠、抗坏血酸和L-半胱甘酸的护色效果有增效作用,而柠檬酸与亚硫酸氢钠和苹果酸之间没有交互作用,柠檬酸浓度的改变不影响这两种褐变抑制剂的作用效果。     

半胱氨酸控制鲜切苹果褐变的生理机制

为研究半胱氨酸对鲜切苹果褐变控制的生理机制,以鲜切苹果为研究对象,采用0.5 g/L的半胱氨酸溶液处 理1 min,分析贮藏过程中鲜切苹果褐变指数（browning index,BI）、多酚氧化酶（polyphenol oxidase,PPO）和 抗氧化酶活力、抗氧化物质和丙二醛（malondialdehyde,MDA）质量摩尔浓度及抗氧化能力的变化。结果表明, 与蒸馏水处理相比,半胱氨酸处理能够显著抑制鲜切苹果的褐变,在贮藏初期半胱氨酸处理降低了鲜切苹果的PPO 活力,同时在贮藏过程中不同程度提高了鲜切苹果的抗氧化酶活力以及抗氧化能力,减缓了抗氧化物质在贮藏过程 中的损失,并且抑制了MDA的积累。相关性分析显示,鲜切苹果的BI值与抗坏血酸含量、过氧化氢酶活力以及抗 氧化能力呈极显著负相关（P＜0.01）,与MDA质量摩尔浓度呈极显著正相关（P＜0.01）。因此,半胱氨酸可能是 一方面通过抑制鲜切苹果的PPO活力,另一方面通过提高其抗氧化能力,延缓贮藏过程中的组织褐变。     

Prevention of enzymatic browning of apple cylinders using different solutions

Inhibition of enzymatic browning and decay on cut surfaces of Golden Delicious apple using ascorbic acid, cysteine, sodium chloride, calcium chloride, citric acid and sodium ascorbate alone or in combinations was investigated at 4 and 10 °C for a storage period of 0, 7 and 14 days, in an attempt to find the most effective treatment. Apple segments immersed in ascorbic acid and citric acid alone showed visual traces of browning after 7 days storage at 4 °C. After 14 days storage, only ascorbic acid and ascorbic acid plus sodium chloride had moderate browning, while all other treatments were severely affected. However, at 10 °C, only ascorbic acid was effective in reducing the level of browning, although its effect was minimal after 14 days storage. Browning was more severe at 10 °C than 4 °C in all solutions. The browning measurement (a* value) became increasingly positive from 7‐ to 14‐day storage. Microbial decay was absent in all treatments within 7 days at 4 and 10 °C. However, three test solutions showed microbial decay after 14 days storage at 10 °C in addition to the control solution, which showed decay at both 4 and 10 °C storage temperatures.     

INTERACTION EFFECTS BETWEEN ASCORBIC ACID AND CALCIUM CHLORIDE IN MINIMIZING BROWNING OF FRESH-CUT GREEN BANANA SLICES

Dopamine level of three banana varieties was determined by spectrophotometry. Dwarf Cavendish banana had the highest browning potential and was used for processing into fresh-cut slices. The slices were treated with anti-browning agents, packed at 55% vacuum level and stored at 10C. A 2  ×  3 factorial treatment structure was used to investigate the interaction effects between ascorbic acid and calcium chloride. At three-day intervals, physico-chemical parameters were investigated. The interaction effect between ascorbic acid and calcium chloride for lightness and redness was significant ( P <  0.05); however, these color parameters were mainly driven by the main effect of ascorbic acid ( P <  0.01). The interaction effect between ascorbic acid and calcium chloride and the main effect of each chemical on firmness were highly significant ( P <  0.01). There was no interaction effect on yellowness ( P >  0.05). Browning and loss of firmness were promoted when 4% calcium chloride was used singly and minimized when 2% ascorbic acid was added.

PRACTICAL APPLICATIONS

Green bananas are widely used in many cooking dishes and utilized in the manufacture of several industrial food products like banana flour, deep-fried chips and baked banana crisps. However, one of the major limitations of green peeled bananas as a raw material, to successfully penetrate the market, is the excessive enzymatic browning after peeling. This badly affects the product's color and decreases the quality of the produce. A combination of naturally occurring substances, calcium chloride (2%) and ascorbic acid (2%) significantly minimized enzymatic browning of green peeled bananas under partial vacuum packaging, while retaining the firmness of the produce and maintaining a shelf life of 12 days at 10C.     

褐变抑制剂对干制香蕉片护色效果的影响

为了提高香蕉片干制后的颜色品质,获得最佳护色方法,以褐变度和L*值为考察指标,研究植酸、抗坏血酸、氯化钠、EDTA、柠檬酸5种褐变抑制剂对干制香蕉片颜色品质影响,并优选出提高干制香蕉片颜色品质的护色方法。结果表明:单一护色剂护色效果依次为植酸柠檬酸EDTA氯化钠抗坏血酸,将鲜切香蕉片放入植酸(质量分数为0.9%)和柠檬酸(质量分数为0.3%)组成的复合护色液中浸泡20 min,干制后的香蕉片L*值达65.93,褐变抑制率达84.4%。     

Biochemical changes in new plantain and cooking banana hybrids at various stages of ripening

BACKGROUND: New varieties of plantain and cooking banana with higher yields and improved pest and disease resistance are continuously being bred. There is therefore the need to study their properties during postharvest ripening. This work investigates the effects of ripening on the dry matter content, pH, titratable acidity, ascorbic acid content, browning potential, starch content and reducing and non‐reducing sugar contents of new FHIA 19 and FHIA 20 plantain and FHIA 03 cooking banana hybrids. RESULTS: The starch and ascorbic acid contents of all hybrids decreased as ripening progressed. The starch and dry matter contents of the FHIA 03 cooking banana were reduced from about 750 to < 100 g kg^?1 and from 260 to 190 g kg^?1 respectively after stage 9 of ripening, when samples had more black than yellow colour. The FHIA 03 cooking banana had the highest content of non‐reducing sugars. The titratable acidity of the FHIA 03 cooking banana was higher than that of the FHIA 19 and FHIA 20 plantains. The browning potential of all hybrids decreased after stage 7 of ripening, when samples were yellow with black spots. The FHIA 19 plantain had the lowest browning potential. CONCLUSION: Significant reductions in the dry matter, ascorbic acid and starch contents of the plantain and cooking banana hybrids were observed during the progress of ripening. The cooking banana variety contained lower levels of dry matter, ascorbic acid and starch than the plantain varieties. Copyright © 2008 Society of Chemical Industry     

复合保鲜剂对鲜切莲藕贮期品质的影响

以二氧化氯预处理后的鲜切莲藕为材料,采用柠檬酸、乙二胺四乙酸二钠、L-半胱氨酸、抗坏血酸对藕片进行复合处理,通过测定藕片褐变度、可溶性固形物、感官品质等指标。结果表明:复合保鲜剂最佳组合为0.8%柠檬酸、0.25%乙二胺四乙酸二钠、0.2%L-半胱氨酸、0.35%抗坏血酸,可有效抑制莲藕褐变,提高贮藏期间产品品质。     

鲜切雪莲果护色保脆效果的研究

以雪莲果为试材,研究鲜切雪莲片护色保脆工艺,筛选出鲜切雪莲果的最佳热烫温度及时间、最佳护色剂以及硬化剂。结果表明：抗坏血酸、半胱氨酸和氯化钠都有抑制褐变的效果,但抗坏血酸的护色效果最好。最优工艺参数为：雪莲果片经热烫处理（70℃,1min）后,用冷水冲洗沥干,依次浸泡于1％抗坏血酸溶液,0．1％氯化钙溶液各10min,料液比为1∶1．5 g/mL,晾干后将雪莲果片放入保鲜袋中密封,4℃低温贮藏,获得颜色、硬度、低聚果糖含量等指标均理想的雪莲果片。     

Effects of Anti-browning Combinations of Ascorbic Acid, Citric Acid, Nitrogen and Carbon Dioxide on the Quality of Banana Smoothies

The effects of 0.2 % ascorbic acid?+?0.2 % citric acid (AA?+?CA), 0.2 % ascorbic acid?+?0.2 % citric acid?+?N₂ (AA?+?CA?+?N₂) and 0.2 % ascorbic acid?+?0.2 % citric acid?+?CO₂ (AA?+?CA?+?CO₂) on the quality of banana smoothies were investigated. An obvious anti-browning effect was observed after each treatment, which resulted from a significant decrease in the polyphenol oxidase activity (p?<?0.05) and the exclusion of oxygen by infusion with inert N₂ or CO₂. The AA?+?CA?+?N₂ treatment exhibited the lowest change of browning index (ΔBI) indicating the best anti-browning effect on the banana smoothies. Compared with the Herschel–Bulkley model, the Power Law was less complex and more suitable for describing the rheological properties of the banana smoothies. AA?+?CA, AA?+?CA?+?N₂ and AA?+?CA?+?CO₂ treatments all significantly increased the pectin methylesterase activity of the banana smoothies (p?<?0.05). The AA?+?CA treatment increased the cumulative volume of the larger particles in the banana smoothies. The viscosity of the banana smoothies decreased after the three different treatments. In terms of the comprehensive results, the inclusion of AA?+?CA?+?N₂ in the production of banana smoothies was the best processing method applied.     

Effect of vacuum impregnation on enzymatic browning of fresh-cut potatoes during refrigerated storage

The effect of vacuum impregnation with ascorbic acid (AA) and calcium ascorbate (CaA) on enzymatic browning of fresh-cut potatoes was investigated. Results showed that vacuum impregnation (VI) with AA-CaA treatment for 2 min had a significant anti-browning effect. VI treatment not only maintained cell membrane integrity, inhibited the key enzyme activities of polyphenol oxidase, peroxidase and phenylalanine ammonia-lyase but also retarded generation of phenolic substrate, particularly chlorogenic acid. Meanwhile, VI promoted AA-CaA solution to infiltrate into potato tissue and delayed loss of ascorbic acid. In conclusion, VI treatment was more efficient for preventing browning with a shorter processing time of 2 min compared to traditional impregnation under atmospheric pressure and could be used as a promising method to inhibit browning of fresh-cut potatoes.     

PREVENTION OF BROWNING OF BANANA SLICES USING NATURAL PRODUCTS AND THEIR DERIVATIVES1

Fresh-cut banana slices were treated with pineapple juice, neutral sugars, isoascorbic acid, citric acid, other organic acids, N-acetylcysteine, 4-hexylresor-cinol and mixtures of these compounds and evaluated for browning reaction. A number of other compounds previously reported to be antibrowning agents were also tested. Preliminary tests revealed that many purported antibrowning agents, including pineapple juice, had only transitory or no effects on browning of banana slices. Subsequent replicated treatments of slices stored at 5C and 15C for 7 days showed that of the several treatments, those using citric acid and N-acetylcysteine were highly effective at reducing browning. Reflectance measurements taken immediately after treatment, after 2 days of storage, and at the end of the 1 week storage period confirmed that a mixture of 0.5 M citric acid and 0.05 M N-acetylcysteine provided the best protection against browning at both temperatures. No microbial decay was observed during the 7 day period studied.