Effect of short‐term air storage after removal from controlled‐atmosphere storage on apple and fresh‐cut apple quality

BACKGROUND: One of the realities of apple distribution for long‐term stored fruit is that a controlled‐atmosphere (CA) storage room will be unsealed and fruit held in air storage and marketed over several weeks. This work was conducted to determine the effect of post‐CA air storage of whole fruit on potential shelf life for fresh‐cut apple slices. RESULTS: Fresh‐cut slices of ‘Spartan’ and ‘Delicious’ apples held in post‐CA air storage for 2 or 4 weeks showed the least changes in cut surface color as compared with those made from apples immediately on removal from CA. Shelf life was most improved by post‐CA air storage in the ‘Spartan’ apples, which were more advanced in maturity as compared with the ‘Delicious’ apples. Internal ethylene concentration, firmness, and respiration changed significantly with post‐CA air storage, suggesting a relationship between physiological status of the whole fruit and shelf life of slices made from that fruit. CONCLUSION: The results support the hypothesis that apples had suppressed physiological activity in CA storage and are susceptible to accelerated deterioration upon cutting. Holding fruit for 2 weeks in air storage allowed recovery of physiological activity, which resulted in greater resistance to deterioration in response to fresh‐cut processing. Copyright © 2010 Crown in the right of Canada. Published by JohnWiley & Sons, Ltd     

Comparative study of improved vs. traditional apple cultivars and their aptitude to be minimally processed as ‘ready to eat’ apple wedges

The development of fresh-cut apple products requires the reconsideration of cultivar selection because different characteristics are required compared with those characteristics for the fresh market. The aim of this work was to evaluate four improved cultivars (‘Modì’, ‘Ariane’, ‘Fuji Kiku 8’ and ‘Pink Lady’) and to compare these cultivars with traditional cultivars (‘Golden Smoothee’ and ‘Granny Smith’). Cultivars were evaluated according to physicochemical parameters and nutritional, enzymatic, and sensory aspects. Next, the cultivars were peeled, cut, treated with different antioxidant treatments, packaged in polypropylene trays and stored at 4 °C. After seven days of storage, physicochemical parameters and visual assessment were determined. As whole apples, the improved cultivars were notable for their sensory characteristics. Moreover, two of them (‘Modì’ and ‘Ariane’) presented the highest amount of total phenols and vitamin C, respectively. After processing and storage, certain of the improved cultivars presented better aptitude for minimal processing. For instance, ‘Modì’ showed high suitability, and ‘Fuji Kiku 8’ was notable for its sensory quality after seven days of refrigerated storage. Among antioxidant treatments that were assayed, 40 g/L NatureSeal^® demonstrated the best results in terms of physicochemical parameters, visual assessment and sensory quality.     

Influence of processing and storage on the antioxidant activity of apple derivatives

The antioxidant activity of seven apple varieties was determined on fresh fruits and processed products (dried fruits and purees) and during storage. The antioxidant activity of apples correlated with the total phenol concentration but not with ascorbic acid concentration. Apple derivatives showed a lower antioxidant activity than the counterparts of the fresh fruits and the occurrence of browning phenomena during processing resulted in lower antioxidant activity. Dried fruits showed higher antioxidant activity per gram of dried matter than fruit purees probably because of the lower total thermal effect of processing. The antioxidant activity of all products increased within the first month of storage, and then declined. The extent of early increase was related to the polyphenol content of the fruit. Packaging conditions further influenced the antioxidant activity increase during storage possibly by affecting the oxygen availability.     

冰温保鲜和冷藏保鲜对生食大西洋鲑品质影响的比较研究

目的探讨冰温保鲜和冷藏保鲜对生食大西洋鲑品质变化的影响。方法将大西洋鲑分别置于-1.8℃冰温条件和4.0℃冷藏条件下贮藏,测定菌落总数、pH值、挥发性盐基氮(total volatile basic nitrogen,TVB-N)值、色差值、K值和感官评分,通过这一系列评价指标,综合分析大西洋鲑在冰温保鲜条件和冷藏保鲜条件下品质变化的不同。结果随着贮藏时间的延长, 2组的菌落总数值、TVB-N值、K值均呈上升趋势, pH值在冰温保鲜条件和冷藏保鲜条件下变化趋势相近,色差值在2个保鲜条件下波动变化没有明显差异,感官评分在2个不同温度条件下总体均呈现下降趋势。在冷藏保鲜条件下,生食大西洋鲑的货架期为2 d;在冰温保鲜条件下,生食大西洋鲑的货架期为5d。结论冰温保鲜方式可将生食大西洋鲑的货架期延长3d,与冷藏保鲜方式相比,冰温保鲜方式在大西洋鲑的贮藏过程中体现了良好的保鲜效果。     

相变蓄冷材料及其在冷库中应用的研究进展

采用文献综述及实际案例相结合的方法,分析了相变材料的特点、蓄冷冷库制冷的原理,以及在实际应用中如何充分发挥各自的优点以达到理想的效果.     

低温等离子体对蓝圆鲹在冷藏过程中的品质影响

目的 研究低温等离子体(atmospheric cold plasma, ACP)对蓝圆鲹在冷藏过程中品质变化的影响。方法 以蓝圆鲹为研究对象,采用介质阻挡放电低温等离子体设备对其进行处理(处理组),新鲜蓝圆鲹为对照组,4℃±1℃的条件下分别贮藏0、2、4、6、8、10 d,通过样品pH、持水力(water holding capacity, WHC)、菌落总数、挥发性盐基氮(total volatile basic nitrogen, TVB-N)、硫代巴比妥酸(thiobarbituric acid, TBARS)值、组胺含量、感官评价等指标来分析蓝圆鲹在冷藏期间的品质变化。结果 随着贮藏时间的延长,两组样品pH呈先下降后上升的趋势;菌落总数由初始值2.97 lg(CFU/g)和3.00 lg(CFU/g)分别上升到6.10 lg(CFU/g)和6.72 lg(CFU/g),处理组菌落总数上升速度较缓;TVB-N值和组胺含量均呈上升的趋势,且随着贮藏时间的延长,对照组比处理组上升速度更为明显;持水力和感官评分随着贮藏时间的延长而明显下降;TBARS值随着贮藏时间的延长而增加,且处理组的TBARS值始终高于对照组。结论 低温等离子体处理能够有效地保持蓝圆鲹的鲜度,尤其是在抑制微生物的增殖方面有较大优势,能够延长蓝圆鲹的货架期至少2 d。本研究为延长蓝圆鲹的货架期提供了一定的理论基础。     

Changes in phenolics,soluble solids,vitamin C,and antioxidant capacity of various cultivars of hardy kiwifruits during cold storage

Food Science and Biotechnology - Hardy kiwifruits (Actinidia arguta) contain various bioactive compounds such as vitamin C and phenolics and can withstand cold temperatures. Changes in soluble...     

Total phenolics,ascorbic acid,and antioxidant capacity of noni (Morinda citrifolia L.) juice and powder as affected by illumination during storage

Total phenolics, ascorbic acid, and antioxidant capacity of noni (Morinda citrifolia L.) juice and powder were determined during storage at 24 °C. After 2 weeks of storage, illuminated noni juice lost 32% of total phenolics, 89% of ascorbic acid, and 46–65% of antioxidant capacity—about 8%, 22%, and 9–15% more than unilluminated juice. Both illuminated and unilluminated juice lost 97% of ascorbic acid by 4 weeks. The difference in antioxidant characteristics between illuminated and unilluminated juice became insignificant at 12 weeks. After 12 weeks, illuminated noni powder lost 21% of total phenolics, 17% of ascorbic acid, and 23–36% of antioxidant capacity—about 13%, 4%, and 7–19% more than the unilluminated powder. Noni powder in brown bottles retained antioxidant characteristics significantly greater than that in clear bottles. Protection from light effectively reduced degradation of antioxidant characteristics of noni juice for only 2 weeks but those of noni powder for at least 3 months.     

Quality changes in oyster (Crassostrea belcheri) during frozen storage as affected by freezing and antioxidant

Changes in physical, chemical, microbiological and sensory qualities of individual quick frozen (IQF) and contact plate frozen (CPF) oyster (Crassostrea belcheri) meat, treated and untreated with butylated hydroxyanisole (0.02% BHA suspension) during storage at −20 °C for 12 months were investigated. Increase in expressible drip of IQF oyster was slower than that of CPF oyster, due to the fact that quick freezing (IQF) resulted in less tissue damage than slow freezing (CPF). Neither freezing method nor antioxidant treatment caused significant changes in chemical qualities, i.e., pH, moisture, crude protein, crude fat and total volatile basic nitrogen (TVB-N), nor in microbiological qualities, i.e., total viable count (TVC), psychrotrophic bacteria, Escherichia coli and Vibrio parahaemolyticus. During frozen storage, TVC and psychrotrophic bacteria of both BHA-treated and untreated CPF oyster decreased with storage time increases (p < 0.05) at a slower rate than in IQF oyster. Antioxidant treatment could minimise sensory quality changes, especially the colour of frozen oyster during storage.     

鲜切芋艿冷藏期间生理及品质变化

以山东威海产芋艿为材料,以整芋为对照,研究了4℃冷藏条件下鲜切芋艿的色差(L*、a*、b*)值、还原糖和抗坏血酸含量、呼吸率、丙二醛、淀粉等指标的变化。结果表明:冷藏期间鲜切芋艿色泽的变化明显,可通过L*、a*、b*值来反映,L*在冷藏期明显下降,a*和b*呈上升势态;同时,切分后的芋艿呼吸强度和丙二醛含量增加;抗坏血酸、还原糖和淀粉等较整芋艿损失多。     

Antioxidant capacity and phenolic content in blueberries as affected by genotype and growing season

Blueberry fruits from five commercial cultivars and 13 breeding selections grown at the same locations over two growing seasons were analysed for total phenolics (TPH), total anthocyanins (ACY), total hydroxycinnamic acids (HCA), total flavonols (FLA), fruit weight and oxygen radical‐absorbing capacity (ORAC). Variation in ORAC, TPH, ACY, HCA, FLA and fruit weight among genotypes was much greater than that observed between growing seasons, indicating that genetics plays a more important role than growing season in influencing ORAC and phenolic content in blueberries. Significant main effects for growing season and genotype × growing season observed for ORAC, ACY, HCA and fruit weight demonstrate that environmental growing conditions can impact levels of phenolics and ORAC in blueberries and that certain genotypes vary in their capacity to synthesise phenolics under different growing conditions. In general, genotypes with smaller berries had higher ORAC values and levels of TPH, ACY, HCA and FLA than large‐berried genotypes. Over both growing seasons, ORAC correlated highly with TPH, ACY, HCA and FLA, while fruit weight correlated inversely with all phenolics measured. Our results indicate that blueberry genotypes should be screened over multiple growing seasons in order to identify antioxidant‐ and phenolic‐rich germplasm. Copyright © 2003 Society of Chemical Industry     

冷库制冷系统及其自动化研究进展

从节能的角度,综述制取环境温度以下到-18℃,-18~-60℃,-60~-100℃3个常用温度区间所对应的高效制冷系统,并且从制冷能效角度分别对单级压缩循环、双级压缩循环、复叠式及自复叠式压缩循环进行分析比较;概述PLC控制、传感器、上位机软件等自动化技术,提出冷库自动化对实现冷库节能的重要性及冷库自控技术未来发展的趋势。     

Influence of apple purée preparation and storage on polyphenol contents and antioxidant activity

The polyphenolic components of Idared and Shampion apple purées were determined by HPLC; chlorogenic acid was the most abundant acid (20.0 mg/100 g in microwaved Idared); other polyphenols identified in high concentrations included (−)-epicatechin, procyanidin B1 and B2; quercetin and cyanidin glycosides were found in minor concentrations. The Shampion purées had higher total phenolics (142 mg/100 g) and procyanidin B2 concentrations (17.3 mg/100 g) than the Idared ones, and polymeric procyanidins represented 41% of all polyphenols. Antioxidant capacities of the samples, determined by spectrophotometric methods and EPR spectroscopy, correlated well with the concentration of polyphenols. The antioxidant properties could be better represented by EPR than by UV–vis measurements. The latter require transparent (clear) samples whereas EPR can be a method of choice in the assessment of radical-scavenging activity of dense and cloudy apple purées. Our results support the putative high antioxidant value of apple purées and define their capacity in terms of the major constituents. Apple purées are a rich source of natural antioxidants, especially of chlorogenic acid and procyanidins.     

Anthocyanins profile,total phenolics and antioxidant activity of black currant ethanolic extracts as influenced by genotype and ethanol concentration

Ethanolic extracts prepared from the fruits of three cultivars of black currant (‘Record’, ‘Blackdown’ and ‘Ronix’) macerated in three concentrations (40%, 60% and 96%) of aqueous ethanol were investigated for their anthocyanins profile, total phenolics and antioxidant activity.     

Cluster analysis of antioxidant compounds in dates (Phoenix dactylifera): Effect of long-term cold storage

Both soft (SD, Bam) and dry (DD, Kharak) date varieties were stored at 4 °C for six months followed by an additional one week storage at 18 °C. Antioxidant compounds (total phenolic content (TPC) and total flavonoid content (TFC)) of the dates increased following storage. Cluster analysis applied on TPC and TFC data before and after storage obtained two statistically significant clusters of SD and DD indicating that TPC and TFC had different behaviors according to the types of dates. As antioxidant concentration in dates was dependent on type of dates, selection of variety with high antioxidant compounds may be recommended. Further cold storage of up to six months followed by one week storage at 18 °C may further improve the level of antioxidant compounds.     

Protein profile and antioxidant capacity of processed seeds from two common bean (Phaseolus vulgaris L.) cultivars

Common bean (Phaseolus vulgaris L.) seeds are an economical protein source rich in bioactive compounds with antioxidant activity. In this work, we evaluated processed seeds from two common bean cultivars regarding protein profile and antioxidant capacity before and after enzymatic digestion in vitro. We provided protein maps by two-dimensional electrophoresis (2-DE) of seeds germinated during 36 h and 72 h. The principal component analysis (PCA) showed that protein abundance had more variation on germination times than the cultivar ones. Seeds germinated for 36 h showed greater antioxidant capacity compared to germination for 72 h and cooking, before and after enzymatic digestion. In protein isolates, cooking associated with digestion provided better antioxidant capacity. Germination time influences protein expression as well as the antioxidant capacity of common beans. Furthermore, in vitro digestion increases the antioxidant capacity of cooked bean protein isolates.