1,720,983 research outputs found
Extending postharvest life of ready-to-use zucchini flowers: Effects of the atmosphere composition
No full textMale zucchini flowers (Cucurbita pepo L.) are greatly appreciated by consumers although, because of their high perishability, they are destined only for local markets. The effects of four different atmosphere compositions (air, 3% O2 in nitrogen, 3% O2 + 10% CO2 in air, and 10% CO2 in air) on quality attributes of fresh zucchini flowers (color, weight loss, respiration, fermentative volatiles, and vitamin C) were studied. Storage in a controlled atmosphere significantly affected postharvest quality and marketability. At 5°C, an atmosphere containing 3% O2 in nitrogen resulted in a reduction in respiration rate and weight loss, preserved visual appearance, sensorial and nutritional quality, and maintained the vitamin C content during the entire storage period. Under these conditions, fresh zucchini flowers were scored marketable and with a good appearance after 9 days of storage. On the other hand, flowers stored in air deteriorated rapidly, resulting in a score just above the limit of marketability (score 3) after 5 days of storage, whereas adding CO2 to air slightly increased flower shelf-life. Flowers stored in air (with or without CO2) showed the same spoilage symptoms, defined by water soaking, wilting and brightness loss, all symptoms that were reduced in a low-oxygen atmosphere. Based on these results, the correct atmosphere conditions for male zucchini flowers should attain low oxygen levels (3%) and avoid excessive accumulation of CO2. Further studies will be needed to investigate the possibility of introducing washing in the processing, due to the high sensitivity of this product to manipulation
Modified atmosphere affected marketability of peeled cactus pear
No full textCactus pear (Opuntia ficus-indica (L.) Mill., 'Gialla') is a delicious and nourishing fresh fruit having a number of documented positive health effects. One of the reasons this fruit is not widely commercialized in international and domestic markets is because of the presence of residual glochids (thorny hairs) on the fruit surface. Marketing cactus pear as a ready to eat product may significantly improve its consumption, preserving its quality, safety and marketability. In this work green-yellow cactus pear fruits were peeled and stored for 13 days at 4 and 8°C, packaged in passive and in active modified atmosphere. Samples stored in air were used as control. The passive modified atmosphere improved the marketability of cactus pears stored at 8°C for 6 days. The rapid decrease in O2and the increase in CO2concentration in packages stored at 8°C caused the loss of marketability of fruits stored at high temperature. Samples stored at 4°C in passive and active modified atmosphere resulted in a marketablility of 9 days, since each one in air was just below the salable limit at 6 days. A very low initial microbial growth was detected, while an increase in mesophilic and psychrophilic bacteria during storage at both temperatures was found in the air samples. In conclusion, it was found that it is possible to store fresh-cut cactus pear, obtaining a marketability of 9 days at 4°C; while, when the temperature is higher than 4°C, it is not possible to preserve the fruit quality for more than 6 days
Postharvest evaluation of soilless-grown table grape during storage in modified atmosphere
No full textBACKGROUND: Soilless growth systems, developed mainly for vegetables and ornamental crops, have also been used recently as an alternative to soil culture for table grape in order to achieve optimal production performance. In this study, sensory, physical and chemical parameters were analysed in table grapes obtained from soil and soilless growth systems at harvest and during storage in air or modified atmosphere.
RESULTS: At harvest, soilless-grown berries were 30% firmer than those grown in soil. Moreover, they showed 60% higher antioxidant activity and total phenol content than soil-grown fruits. Modified atmosphere storage resulted in a better quality of table grapes comparedwith those stored in air. Furthermore, soilless growth wasmore suitable than soil growth for preserving visual quality and controlling rachis browning and weight loss.
CONCLUSION: Since the soilless system produces berries that are cleaner and of higher quality than those grown in soil, the implementation of soilless growth for the production of health-promoting and convenience fruits is suggested
Computational Modelling of Modified Atmosphere Packaging: Application to Cactus Pear and Truffle as Case Studies
No full textShelf life improvement for two different products (cactus pears and truffles),
stored at 8 and 5°C respectively under modified atmosphere packaging (MAP), was
assessed by modelling heat and mass transport as well as package geometry and
storage conditions. An innovative approach was implemented by coupling an
engineering tool, such as the computational fluid dynamics (CFD) with experimental
data, such as visual quality, respiration rate, head space composition, and weight
loss upon MAP storage. The overall model, incorporating all phenomenological
variations, has been finally tuned-up by means of a specific multi-objective
optimization. It is seen that the models are able to simulate complex,
multidimensional food-package ensembles under MAP conditions.
As for cactus pears, a multidimensional, transient model is proposed by
combining generalized transport notations with respiration and microbial growth
kinetics.
As for truffles, a model able to predict the effect of storage on quality loss was
obtained.
The adoption of predictive and comprehensive mathematical models is an
economic method to evaluate packaging and operating performance, compared to
more expensive experimental methods. Computational models, such as these, can be
used to verify existing MAP configurations, or to design new ones. Exploitation of
this mathematical tool would allow for informed technical and management
decisions
Compositional and Marketable Quality of Fresh-Cut Florets of Four Specialty Brassicas in Relation to Controlled Atmosphere Storage
No full textBrassica vegetables are consumed year-round as raw salad or cooked ingredients. Four Brassica species were selected for this study, broccoli (Brassica oleracea var. italica), broccoli raab (Brassica rapa L.), choisum (Brassica rapa var. parachinensis), and gailan (Brassica oleracea var. alboglabra). While there is abundant information about broccoli, research on gailan, choisum and broccoli raab is very limited. The effect of CA (3% O-2 alone or in combination with 7 or 15% CO2, 1% O-2 alone or combined with 15% CO2) and air on marketable quality (overall visual, yellowing, discoloration, decay) and chemical parameters (antioxidant activity, chlorophyll, sugar, fermentative volatiles, and ammonia content) during storage at 5 degrees C was evaluated. Products were obtained from a wholesaler, washed in chlorinated water, trimmed into florets and placed in unsealed polyethylene bags that were held in polycarbonate chambers through which humidified air or the controlled atmospheres flowed. Visual quality was evaluated after 0, 8, 12, 16 and 20 days, while chemical parameters were measured after 0, 8, 16 days. Generally, CA treatments did not affect the antioxidant activity, chlorophyll or sugar concentrations in any of the specialty brassicas studied. On the other hand, both ammonia content and visual quality evaluations were affected by atmosphere composition. Florets stored in low oxygen (3% O-2) often had the best visual quality but generally all atmospheres maintained better marketable quality than air storage. The 3% oxygen CA improved marketability to about 16 days. Low oxygen delayed postharvest and post-cutting deterioration of florets from all Brassica species, and based on changes in ammonia concentrations, was considered beneficial to maintain quality of fresh-cut brassicas stored at 5 degrees C
Design of the correct modified atmosphere packaging for fresh-cut broccoli raab
No full textA low-oxygen controlled atmosphere has been reported to be useful in maintaining freshness and qualitative traits of fresh-cut broccoli raab during cold storage, while excessive accumulation of CO2 (10-15%) should be avoided. Starting from these previous findings, the aim of this work was to select the correct modified atmosphere packaging (MAP) for fresh-cut broccoli raab in order to reach, at equilibrium, the target low-oxygen (3%) atmosphere during cold storage. Broccoli raab harvested from a commercial farm was sorted to remove defects and cut from the stalks, obtaining the ready-to-use product. After washing, the product was packaged in plastic trays sealed in bags of different plastic materials. Two commercially available polymeric laminated films [polypropylene/polyethylene terephthalate (PP/PET) and microperforated polypropylene/polyamide (PP/PA)] were used with or without the inclusion of a CO2 absorber (5-g sachet). For each package type, a passive atmosphere (P-MAP) and an active atmosphere achieved by flushing with 5% O2 in nitrogen (A-MAP) were used. Unpackaged samples were used as controls and stored with all packages at 5°C. Quality attributes (overall appearance, odor, color, and weight loss) were evaluated initially and after 3 and 8 days. Gas concentrations (O2 and CO2) inside packages were also monitored. Among the packaging treatments tested, the combination using PP/PA in A-MAP with the use of CO2-absorbing sachets reached an equilibrium condition very close to optimal for broccoli raab (5% O2 and ≤5% CO2). Fresh-cut broccoli raab stored under these conditions for 8 days showed negligible reduction of appearance and odor scores, and product was comparable to the fresh samples
Effect of atmosphere composition on the quality of ready-to-use broccoli raab (Brassica rapa L.)
Full text linkBACKGROUND: Many leafy brassicas are widely used for ready-to-use salads. Broccoli raab (Brassica rapa L.), also called turnip top, or rapini, is extensively cultivated in southern Italy. The edible portion is made up of the green, immature inflorescences and the stem with itsmost tender leaves. Recently, interest in this crop has increased among European consumers; moreover, a substantial increase in consumption could come from the ready-to-use product.
RESULTS: The effects of four different atmosphere compositions (air,3%O2 in nitrogen, 3%O2 +10%CO2 in air, and 10% CO2 in air) on quality attributes of ready-to-use broccoli raab were studied. Controlled atmosphere affected appearance, composition, respiration rate, weight loss, and presence of off-odours. Storage of broccoli raab florets under low oxygen conditions delayed post-cutting deterioration during storage at 5 ◦C and preserved appearance and typical odour, up to 17 days. Moreover, respiration rate as well as loss of green colour, chlorophyll and vitamin C were also slowed down in this condition. Finally, in this study no effect of controlled atmosphere storage was found on total phenols content and antioxidant activity.
CONCLUSION: Results showed that cold storage in 3%O2 can be beneficial in order tomaintain quality of ready-to-use, broccoli raab for up to 17 days
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Computer vision system based on conventional imaging for non-destructively evaluating quality attributes in fresh and packaged fruit and vegetables
No full textQuality assessment of fresh fruit and vegetables is an arduous and complex process which needs very intensive labour of correlation among sensory and subjective determinations and conventional destructive methods. Consumers' requests for fruit and vegetables with high quality in terms of appearance, nutritional value and safety have prompted industries and researchers to develop rapid, precise and low-cost techniques for food analysis. Among innovative techniques, image analysis by computer vision systems based on conventional imaging (CVS-CI) have proved to be effective and suitable for application at industrial level. This review summarizes developments on CVS-CI technology for the evaluation, along the entire distribution chain, of external defects, colour changes and internal chemical-physical attributes of fresh fruit and vegetables, with or without the presence of plastic packaging. The most interesting researches carried out during the last ten years on CVS-CI employments are reported and discussed. The description of each application points out the performances obtained, the hardware components, the image processing techniques used to extract information from the images acquired, the classification/regression models used to grade products and to estimate their quality traits. Finally, future perspectives and possible new applications of CVS-CI in postharvest field are proposed
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