Effects of a pretreatment with nitric oxide on peach (<Emphasis Type="Italic">Prunus persica</Emphasis> L.) storage at room temperature

Peach is characterised by a rapid senescence associated with a high production of autocatalytic ethylene at the beginning of ripening, a fact which reduces markedly its postharvest shelf-life. The application of antisenescent compounds after harvesting has been assayed to solve this problem. One of the newest and more promising compounds is the free radical gas nitric oxide (NO). In this work, peaches of cv. ‘Rojo Rito’ were treated with 5 μL L⁻¹ of NO for 4 h, at 20 °C, and then stored at the same temperature for 14 days. Untreated fruits stored under the same conditions were used as control fruits in the experiment. Key physiological parameters of senescence (ethylene production and respiratory rate) and quality parameters (firmness, titrable acidity, total soluble solids and colour) were analysed. A particular emphasis was placed on the analysis of the oxidative status and the antioxidant capacity during storage and as a response to the NO treatment. The ethylene production and respiratory rate of fruits treated with NO were lower than those of control fruits. Treated fruits underwent a lesser loss of firmness during storage. The degree of disintegration of cell membranes, assessed as the percentage of electrolyte leakage, was also lower in fruits treated with NO. NO did not seem to affect lipid peroxidation or LOX activity, but it did affect PPO activity. The treatment with NO stimulated POX activity and, especially, SOD and CAT activities. It seems that total carotenoids and free ASC were not influenced by the pretreatment; however, the oxidised form of ASC, DHA, showed a slight increase. NO seemed to have a beneficial effect on the oxidation equilibrium and the antioxidant capacity of peach fruit. A delay in the initiation of the senescence of fruits treated with NO, that extended the postharvest shelf-life, was observed.     

Advances and Strategies for Controlling the Quality and Safety of Postharvest Fruit

Fresh fruits are highly valued by consumers worldwide, owing to their delicious flavors, abundant nutrients, and health-promoting characteristics, and as such, fruits make up an important component of a healthy diet. The postharvest quality and safety of fresh fruit involve complex interactions among the fruit, environmental factors, and postharvest pathogens. Efficient regulation of fruit senescence and pathogen resistance, as well as disease-causing abilities of postharvest pathogens, is critical to understanding the fundamental mechanisms that underlie fruit quality and safety. This paper provides a comprehensive review of recent advances and currently available strategies for maintaining fruit quality and controlling major postharvest pathogens, mainly Botrytis cinerea and Penicillium expansum, which may promote sustainable and environmental-friendly development of the fruit industry.     

Identifying and evaluating farmer deviations from steps recommended for hermetic postharvest storage of beans in northern Mozambique

Despite the fact of calls for studies to identify and assess the effects of user deviations from recommended innovation-practices disseminated to farmers in developing-nation contexts, such research remains rare. This study answers that call by drawing on prior research—which two years earlier had trained farmers in northern Mozambique in an 8-step, improved postharvest bean storage protocol using jerrycans—to investigate deviations (“reinventions”) by users from that protocol’s recommended practices. Results from this study found that while 91.3% of participants had used the storage innovation method at least once (high adoption), nearly half (45%) had deviated in at least one way from the eight recommended steps, with none (0%) reporting any failure of the innovation. Deviations consisted of two major types: skipping at least one of the eight steps (approximately 1 in 3 participants) and adding a step or element to the method (approximately 1 in 5 participants). These combined findings of high adoption, reinvention, and storage method effectiveness provide innovation designers and suppliers insights into the potentially crucial role of reinvention for successfully diffusing stored product innovations in developing nation contexts. The importance of further research into a means for assessing when reinvention has positive, neutral, or negative impacts on innovation goals is also discussed.     

Assessment of quantitative and qualitative losses of stored grains due to insect infestation in Ethiopia

This study was designed to determine the quantitative and qualitative losses of stored grains that arise from insect infestation in three districts of southwestern Ethiopia. One district was selected from each zone based on the production potential of the target crops (maize, sorghum, wheat and fababean). A total of 240 farmers’ stores from all districts were randomly selected. The grain samples used in the present study were stored for 5 different time periods, ranging from 1 to 5 months and from the same farmers’ stores, to determine grain weight loss, insect damage, and nutritional losses. Grain damage showed significant differences over the storage periods across the study districts. A similar trend was observed for weight loss for each of the grains in all districts. The moisture content of the grains decreased along the storage duration. Crude protein and crude fat contents significantly decreased as the storage duration increased in all traditional storage types. Furthermore, the crude fibre and ash contents of the different grain types significantly increased as the storage duration increased in all storage types. These results demonstrated that traditional storage structures have a substantial effect on quantitative and qualitative losses of stored grains. This finding has great implications for food security and hidden nutritional deficits in society. Thus, there is a need to develop and disseminate storage technologies that minimize losses and that are affordable for small farm holders.     

Economic and nutritional implications of losses and contributing factors along the bean value chain

The contribution of food availability to food insecurity and poverty reduction, makes food loss an important issue. The study provides findings on the economic and nutritional implications of produce loss at different stages of the common bean value chain and discuss farmers role in reducing losses through their measurement of loss and awareness of loss factors. Average losses at the postharvest handling stage, storage and marketing stage were estimated to be 85.6%, 11.6% and 2.8% of the total loss along the chain respectively. The analysis was extended to determining the economic and nutrient losses along the value chain. Losses contributes to economic losses of $269,417.6 and $8,035.2 at the production and marketing stages respectively. The true cost based on value added loss estimations was however found to be $423,737.8 at the production stage. Findings revealed that out of the total nutrients lost at the post harvest handling stage contributes (88.07%) contributes to majority of the losses compared to the storage stage (11.93%). Losses were found to be caused by unfavourable weather, seed quality, insects, diseases and inefficient handling practices. More than 60% of both producers and traders measured their losses and had a fair understanding of the factors causing losses with a significant difference being observed between measurers and non-measurers. Lack of awareness was not found to be a contributing factor to losses but inability to manage them. Improvement in the capacity of agents to better manage losses is expected to result in lower levels of losses.     

Spread of Aspergillus flavus and aflatoxin accumulation in postharvested maize treated with biocontrol products

Maize is a major staple crop and calorie source for many people living in Sub-Saharan Africa. In this region, Aspergillus flavus causes ear rot in maize, contributing to food insecurity due to aflatoxin contamination. The biological control principle of competitive exclusion has been applied in both the United States and Africa to reduce aflatoxin levels in maize grain at harvest by introducing atoxigenic strains that out-compete toxigenic strains. The goal of this study was to determine if the efficacy of preharvest biocontrol treatments carry over into the postharvest drying period, the time between harvest and the point when grain moisture is safe for storage. In Sub-Sahara Africa, this period often is extended by weather and the complexities of postharvest drying practices. Maize grain was collected from fields in Texas and North Carolina that were treated with commercial biocontrol products and untreated control fields. To simulate moisture conditions similar to those experienced by farmers during drying in Sub-Sahara Africa, we adjusted the grain to 20% moisture content and incubated it at 28 °C for 6 days. Although the initial number of kernels infected by fungal species was high in most samples, less than 24% of kernels were infected with Aspergillus flavus and aflatoxin levels were low (<4 ppb). Both toxigenic and atoxigenic strains grew and spread through the grain over the incubation period, and aflatoxin levels increased, even in samples from biocontrol-treated fields. Our molecular analysis suggests that applied biocontrol strains from treated fields may have migrated to untreated fields. These results also indicate that the population of toxigenic A. flavus in the harvested grain will increase and produce aflatoxin during the drying period when moisture is high. Therefore, we conclude that preharvest biocontrol applications will not replace the need for better postharvest practices that reduce the drying time between harvest and storage.     

Effect of gaseous chlorine dioxide treatment on the quality of rice and wheat grain

Gaseous chlorine dioxide (ClO₂), which is a strong disinfecting agent with strong oxidation properties and penetration ability, is used to control insect pests and fungal contamination in stored grains. However, the effect of gaseous ClO₂ on stored grain has yet to be reported. In the present study, we exposed rice and wheat seeds to several concentrations of ClO₂ gas for various durations and found that the viability of rice was affected less than that of wheat. After 100 ppm of gaseous ClO₂ for 12 h, the normal rice seedling rate was not significantly different than that of the control. However, that of wheat was significantly decreased. We also measured the ClO₂ residueon stored rice and wheat after 200 ppm of gas treatment for 24 h. After 10 days of storage following the treatment, ClO₂ and chlorine were not detected on either rice or wheat. Chlorite was detected on rice at 0.22 mg/kg of grain; however, it was not detected on wheat. These results suggest that gaseous ClO₂ treatment affects the viability of rice and wheat seed but leaves minimal chemical residue.     

Horticultural characteristics and chemical composition of advanced raspberry lines from Quebec and Ontario

Three advanced raspberry (Rubus idaeus L.) lines from the University of Guelph breeding program (‘88-18’, ‘88-117’, ‘88-134’) and one advanced line from the Quebec fruit breeding program (‘SJR942-7’) were tested for their winter hardiness, fruit quality, horticultural characteristics and antioxidant activity compared to four commercially grown cultivars (‘Festival’, ‘Boyne’, ‘Nova’ and ‘Killarney’) recommended for Quebec. Lines ‘88-18’ from Guelph and ‘SJR942-7’ from Quebec had higher antioxidant activity, larger fruit size, better fruit quality and longer shelf life than all other lines and cultivars tested. The ellagic acid content of ‘SJR942-7’ was approximately two times higher than that of the commercial cultivars grown in Quebec.     

Frequency and time pattern differences in acoustic signals produced by Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) and Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) in stored maize

Frequency spectra and timing patterns of brief, 1–10 ms broadband sound impulses produced by movement and feeding activities of Prostephanus truncatus and Sitophilus zeamais last instars and adults in maize were investigated to find spectral and temporal pattern information useful for distinguishing among these species and stages. The impulse spectra were categorized into five different types of frequency patterns (profiles), designated Broadband, HighF, MidF1, MidF2 and LowF to indicate differences in their peak energies and broadness of frequency range. Groups (trains) of three or more closely spaced impulses, termed bursts, were observed to occur frequently in all recordings, as has been reported for sounds produced by other insects. Mean rates of bursts, mean counts of impulses per burst, and mean rates of impulses in bursts were calculated and compared among the two species and stages. The counts of broadband and MidF2 impulses per burst and the rates of broadband and MidF2 impulses in bursts were significantly different for adult than for 4th instar S. zeamais and either stage of P. truncatus. These findings can be useful in developing an acoustic sensor system for automated detection of hidden insects including P. truncatus and S. zeamais in bulk storage warehouses. The findings are discussed in relation to different movement and feeding behavior patterns that have been identified in these important pests.     

Sweet cherry: Composition,postharvest preservation,processing and trends for its future use

BackgroundSweet cherries (Prunus avium L.) are a nutritious fruit which are rich in polyphenols and have high antioxidant potential. Most sweet cherries are consumed fresh and a small proportion of the total sweet cherries production is value added to make processed food products. Sweet cherries are highly perishable fruit with a short harvest season, therefore extensive preservation and processing methods have been developed for the extension of their shelf-life and distribution of their products.Scope and approachIn this review, the main physicochemical properties of sweet cherries, as well as bioactive components and their determination methods are described. The study emphasises the recent progress of postharvest technology, such as controlled/modified atmosphere storage, edible coatings, irradiation, and biological control agents, to maintain sweet cherries for the fresh market. Valorisations of second-grade sweet cherries, as well as trends for the diversification of cherry products for future studies are also discussed.Key findings and conclusionsSweet cherry fruit have a short harvest period and marketing window. The major loss in quality after harvest include moisture loss, softening, decay and stem browning. Without compromising their eating quality, the extension in fruit quality and shelf-life for sweet cherries is feasible by means of combination of good handling practice and applications of appropriate postharvest technology. With the drive of health-food sector, the potential of using second class cherries including cherry stems as a source of bioactive compound extraction is high, as cherry fruit is well-known for being rich in health-promoting components.