Changes of physicochemical and sensory characteristics of packed ripe table olives from Spanish cultivars during shelf‐life

Changes in the physicochemical and sensory characteristics of commercial plain (whole) and pitted ripe olives of the Gordal, Manzanilla, Hojiblanca and Cacereña cultivars were studied during a three‐year period in conditions that mimicking the storage of such products in real life. No spoilage was developed during this period. Throughout the shelf‐life, the pH of the cover brines had a marked valley decrease at the beginning of storage followed by a progressive further decline, the surface colour (measured instrumentally) and firmness of the olives followed a first‐order kinetic decay, mitigated according to the iron and calcium contents. Also, a slight browning of the cover brines at the beginning of the storage was observed. No significant changes in most of the sensory characteristics were observed by the panel test during shelf‐life except for a limited change in olive surface colour. At the end of the shelf‐life, most of the samples were classified as ‘extra’ category according to the IOC sensory evaluation method and only plain Gordal presentation was classified as ‘first, choice or select’.     

1-MCP处理结合冰温贮藏对富士苹果生理品质的影响

研究1-MCP处理结合冰温贮藏对富士苹果感官品质、生理生化以及相关酶活性的影响。结果表明:1-MCP处理能完全抑制富士苹果在贮后货架期间果实腐烂,延长货架期,显著地降低果实的呼吸强度、乙烯生成速率,保持果实硬度、可溶性固形物含量,抑制多酚氧化酶（PPO）、脂氧合酶（LOX）活性,有效地诱导过氧化物酶（POD）、过氧化氢酶（CAT）活性峰的出现,且冰温贮藏可使1-MCP更好地发挥作用。      

The effect of wholesale vacuum and 100% CO2 storage on the subsequent microbiological, colour and acceptability attributes of PVC-overwrapped pork loin chops

The shelf life of chops cut from pork loins, after either vacuum or 100% CO₂ storage (0, 7 or 14 days), was determined. The PVC-overwrapped chops were assessed, following a shelf life study of 0, 2, 5 or 7 days at 0 or 5°C, regarding quality attributes such as microbiological contamination levels, colour and acceptability. The study indicated that according to the psychrotrophic counts, the PVC-overwrapped retail chops, from the vacuum as well as the 100% CO₂ stored pork loins (0, 7 or 14 days), still attained a conventional shelf life of 3 days.

Lactic acid bacteria and pseudomonads largely represented the psychrotrophic counts. No clear pattern could be detected regarding the colour scores except that the samples displayed at 0°C tended to retain colour longer. These samples were also judged to be more acceptable, although the determination of acceptability was subjective.     

包装方式对四角蛤蜊卤制风味产品贮藏品质的影响

目的：研究不同包装方式对其贮藏期品质的影响。方法 对四角蛤蜊卤制风味产品进行普通包装、真空包装、30% CO2+70% N2、50% CO2+50% N2、30% N2+70% CO2气调包装,并在4 ℃贮藏条件下,测定菌落总数、质构特性、色差、TVB-N值、风味特性等理化指标,选择最佳的包装方式。结果 普通包装样品在第3 d、真空包装组样品在第6 d时菌落总数超标,而气调包装组的货架期可达12 d左右。气调包装组的硬度、弹性、咀嚼性的下降程度都低于普通包装和真空包装组,气调包装的护色效果也优于其他两组。气调包装对TVB-N值、TBA值、pH值变化的延缓作用明显优于真空包装和普通包装。结论 不同包装方式对四角蛤蜊卤制风味产品贮藏品质的保持能力依次为气调包装、真空包装、普通包装,其中50% CO2+50% N2气调包装保鲜效果最佳,能显著延长产品货架期。     

The quality of frozen African sharptooth catfish (Clarias gariepinus) fillets under long‐term storage conditions

The quality of frozen catfish fillets was monitored over a period of 11 months at ?20 °C, in two types of packaging materials, namely vacuum packaging (VP) and oxygen‐permeable packaging (OPP). Representative samples (n = 5) from both types of packaging materials were drawn at random, monthly for the full period of the trial. Samples were pooled and analysed microbiologically using standard methods. Fatty acid analyses of total lipids, neutral lipid, glycolipid and phospholipid fractions as well as sensory evaluation were also conducted every 3 months on the pooled samples. These tests were conducted to determine whether OPP (cheaper option) could be used instead of VP for long‐term superchilling of catfish without detracting from its quality. Low microbiological counts were maintained throughout the trial, ie 4.1 × 10⁴ cfu g^?1 (VP) and 8.9 × 10⁴ cfu g^?1 (OPP) in the 11th month for aerobic plate count. No significant human pathogens were isolated, with the exception of Aeromonas hydrophila (Stanier). Lipid oxidation, irrespective of packaging, showed no fixed trends during the 11 months of investigation. Also, no significant deviation from sensory characteristics was noted. These results indicate that storing catfish fillets in OPP is a feasible and cheaper option for long‐term freezing. © 2001 Society of Chemical Industry     

Physicochemical, microbial, and sensory properties of yogurt supplemented with nanopowdered chitosan during storage

This study was carried out to determine the possibility of adding nanopowdered chitosan (NPC) into cholesterol-reduced yogurt to improve the functionality of yogurt and the effects of adding NPC on the physicochemical, microbial, and sensory properties of the products during storage. The pH values and mean lactic acid bacteria counts of NPC-added (0.3 to ∼0.7%, wt/vol) and cholesterol-reduced yogurt ranged from 4.19 to 4.41 and from 4.75 × 10⁸ to 9.70 × 10⁸ cfu/mL, respectively, when stored at 4°C for 20 d, thereby indicating a possibility of prolonging the shelf life of yogurt. In color, the a* and b* values for cholesterol-reduced yogurt were not significantly influenced by the addition of NPC (0.1 to ∼0.7%, wt/vol); however, the L* values significantly decreased with the addition of the greatest concentration (0.7%, wt/vol) of NPC at 0-d storage. The sensory test revealed that the astringency scores significantly increased at 0-d storage when the greatest concentration (0.7%, wt/vol) of NPC was added into cholesterol-reduced yogurt. Based on the data obtained from the current study, it is concluded that concentrations (0.3 to ∼0.5%, vol/vol) of NPC could be used to produce an NPC-added and cholesterol-reduced yogurt without significantly adverse effects on the physicochemical, microbial, and sensory properties.     

Differences in chemical, microbial and sensory quality parameters of the marinated ascidia Microcosmus sabatieri Roule, 1885 during storage at 6 °C under vacuum conditions

Chemical, microbial and sensory quality aspects of the marinated ascidia Microcosmus sabatieri Roule, 1885, were examined over a 150-day period at 6 °C, under vacuum and air (control) packaging conditions using three different formulations (with 12% sodium chloride and 3%, 5% or 7% acetic acid). Significant differences were found between chemical and sensory analysis of three different marinated groups ( P  > 0.05) during the storage period. There were also significant differences in pseudomonads, lactic acid bacteria and yeast and moulds of the marinated groups by which lower bacterial counts were determined. N -3 polyunsaturated fatty acids concentrations decreased significantly ( P  < 0.05), while total viable counts, ammonia and total saturated fatty acid concentrations increased significantly ( P  > 0.05) in all three groups during storage. The differences in fatty acid and ammonia concentrations were found to be useful as indexes of freshness and decomposition of marinated M. sabatieri in storage. Shelf life of M. sabatieri marinades was found to be 5 and 4 months under vacuum and air (control) packaging conditions respectively, at 6 °C.     

Mechanical behaviour and quality traits of highbush blueberry during postharvest storage

BACKGROUND: Berry firmness is one of the most important characteristics for fresh market consumption. Blueberry firmness is also an important attribute because it is considered to be a measure of its freshness. Berries lose their firmness by loss of water and by changes in their structure. RESULTS: The postharvest life of two highbush blueberry cultivars (Bluecrop and Coville) was investigated. Several parameters related to blueberry quality were evaluated during the postharvest storage period. To assess berry texture characteristics (firmness, hardness, cohesiveness, gumminess, chewiness, springiness, resilience), a rapid non‐destructive penetrometer test by Durofel^® and texture profile analysis (TPA) using a texture analyser were carried out. Low temperature inhibited the decrease of total soluble solids, total titratable acidity and increase of flesh pH value, thereby maintaining good taste quality. There was an increase in fruit firmness (Durofel index) and hardness and a decrease in chewiness and springiness during storage. CONCLUSION: There was a significant correlation among the TPA parameters and Durofel index. The Durofel index could therefore be used as a suitable indicator of fruit quality and storability, and low‐temperature storage is beneficial to maintain the taste quality of blueberry fruit after harvest. Copyright © 2009 Society of Chemical Industry     

Effect of nano‐TiO2‐LDPE packaging on microbiological and physicochemical quality of Pacific white shrimp during chilled storage

Nano‐TiO₂‐modified low‐density polyethylene (NTLDPE) packaging was prepared by blending LDPE with nano‐TiO₂. The effects of NTLDPE packaging on quality of Pacific white shrimp during storage at 4 °C were investigated. Results showed that NTLDPE lowered the K value by 28.50%, while increased sensory score by 30.77% in comparison with the control. NTLDPE packaging retarded the decrease of whiteness and water holding capacity and the increase of melanosis score based on the signs of freshness and deterioration of shrimp. Furthermore, NTLDPE packaging reduced total viable counts (TVC) by 6.42% and total volatile basic nitrogen (TVB‐N) contents were 14.82% lower than that of control. TVB‐N content and TBARS value, as well as polyphenol oxidase activity and TVC, were maintained and shrimp remained a commercial acceptability for 8 days. The overall results indicated that NTLDPE packaging could preserve the quality and extend the shelf‐life of Pacific white shrimp.     

Effect of sub‐freezing storage (−6, −9 and −12 °C) on quality and shelf life of beef

Based on the results of low field nuclear magnetic resonance (LF‐NMR) in our current study (the frozen state of ?6, ?9 and ?12 °C were nearly the same with extremely low free water content), ?6, ?9 and ?12 °C was designated as sub‐freezing temperatures. The effects of sub‐freezing storage compared with conventional chilling (4 °C), superchilling (?1 °C) and conventional freezing (?18 °C) on the quality and shelf life of beef were analysed. Results showed that the shelf life of beef is extended to 84 and 126 day at ?6 °C and ?9 °C, respectively. However, the TVB‐N values of the samples stored at ?12 °C and ?18 °C remained below 15 mg/100 g even on 168 day. Furthermore, shear force, colour, pH, thiobarbituric acid reactive substances (TBARS) and sensory properties were also measured. Consequently, the sub‐freezing storage has significantly extended the shelf life of beef compared to chilling and superchilling (P < 0.05). Moreover, no significant difference (P > 0.05) was found between the indicators for quality and shelf life of samples stored at ?12 and ?18 °C throughout 168 days.     

Evaluation of heat and oxidative damage during storage of processed tomato products. I. Study of heat damage indices

The evolution of heat damage during storage of tomato pulp, puree and paste was studied by accelerated aging tests. Heat damage indices—5‐hydroxymethyl‐2‐furfural (HMF), furosine and colour changes (ΔE)—were evaluated for tomato products stored at 30, 40 and 50 °C for up to 90 days. Furosine and ΔE values increased following pseudo‐zero‐order kinetics, and the higher the solid content of the products, the higher were the rate constant values. HMF formation followed pseudo‐first‐order kinetics in tomato pulp and pseudo‐zero‐order kinetics in puree and paste samples. Data show that heat damage reactions in tomato products proceed even at room temperature, and the kinetic model provided can be used to predict changes occurring during shelf‐life. © 2002 Society of Chemical Industry     

Changes in aroma quality of ‘Golden Delicious’ apples after storage at different oxygen and carbon dioxide concentrations

‘Golden Delicious’ apples were stored in semicommercial chambers in normal atmosphere and in various controlled atmospheres (CAs) in which oxygen and carbon dioxide contents were held at 10, 20 or 30 l m⁻³ for 3, 5 or 7 months. Following storage, fruits were kept at 20 °C for 1, 5 or 10 days, after which quality parameters were determined and aroma components were obtained and analysed by the dynamic headspace method and quantified by gas chromatography–mass spectrometry. The highest emission of volatile components was obtained after 5 months of storage. Esters were the main compounds released after cold storage in all conditions. Normal cold storage gave the highest amounts of straight‐chain esters, while low‐oxygen atmospheres gave the highest amounts of branched‐chain esters. After 3 and 7 months there were no significant differences in volatiles on comparing fruits from different storage conditions. Low‐oxygen atmospheres had beneficial effects on fruit firmness, titratable acidity and colour. Apples coming from low‐oxygen atmospheres gave the highest sensory score after 5 months of cold storage. © 2000 Society of Chemical Industry     

Effect of controlled atmospheres and shelf life period on concentrations of volatile substances released by ‘Pink Lady®’ apples and on consumer acceptance

BACKGROUND: ‘Pink Lady^®’ (Malus × domestica Borkh.) apples were harvested at commercial maturity and stored at 1 °C under either air or controlled atmosphere (CA) conditions (2.5 kPa O₂: 3 kPa CO₂ and 1 kPa O₂: 2 kPa CO₂) for 15 or 28 weeks. Standard quality parameters, consumer acceptance and volatile compound emission were evaluated after cold storage plus shelf life period at 20 °C. RESULTS: A shelf life period of 17 days after long‐term storage in controlled atmosphere allowed the regeneration of the characteristic esters associated to the aroma of this variety. Sixty‐five per cent of consumers preferred apples with higher emissions of aroma‐active volatile compounds, despite the fact that these apples displayed lower values for standard quality attributes. The most accepted samples corresponded to fruit stored in air for 15 weeks regardless of post‐storage period, in air for 28 weeks plus 1 day at 20 °C, and in 2.5 kPa O₂: 3 kPa CO₂ for 15 weeks plus 7 days at 20 °C. CONCLUSIONS: Concentrations of specific aroma volatile compounds are suggested to be more important than total aroma emission for consumer acceptance of ‘Pink Lady^®’ apples. Copyright © 2009 Society of Chemical Industry