Postharvest Management of Fruits and Vegetables

All articles in the presented collection are high-quality examples of both basic and applied research. The publications collectively refer to apples, bananas, cherries, kiwi fruit, mango, grapes, green bean pods, pomegranates, sweet pepper, sweet potato tubers and tomato and are aimed at improving the postharvest quality and storage extension of fresh produce. The experimental works include the following postharvest treatments: 1-methylcycloprpene, methyl jasmonate, immersion in edible coatings (aloe, chitosan, plant extracts, nanoemulsions, ethanol, ascorbic acid and essential oils solutions), heat treatments, packaging, innovative packaging materials, low temperature, low O2 and high CO2 modified atmosphere, and non-destructible technique development to measure soluble solids with infra- and near infra-red spectroscopy. Preharvest treatments were also included, such as chitosan application, fruit kept on the vine, and cultivation under far-red light. Quality assessment was dependent on species, treatment and storage conditions in each case and included evaluation of color, bruising, water loss, organoleptic estimation and texture changes in addition to changes in the concentrations of sugars, organic acids, amino acids, fatty acids, carotenoids, tocopherols, phytosterols, phenolic compounds and aroma volatiles. Gene transcription related to ethylene biosynthesis, modification of cell wall components, synthesis of aroma compounds and lipid metabolism were also the focus of some of the articles

Transpiration and moisture evolution in packaged fresh horticultural produce and the role of integrated mathematical models: A review

Transpiration has various adverse effects on postharvest quality and the shelf-life of fresh fruit and vegetables (FFV). If not controlled, the water released through this process results in direct mass loss and moisture condensation inside packaged FFV. Condensation represents a threat to the product quality as water may accumulate on the product surface and/or packaging system, causing defects in external appearance and promoting growth of spoilage microorganisms. Thus, moisture regulation is extremely important for extending FFV shelf-life. This review focuses on transpiration phenomenon and moisture evolution in packaged fresh horticultural produce. It provides recent information on various moisture control strategies suitable for packaging of fresh horticultural produce. It also provides an evaluation on the role and application of integrative mathematical modelling in describing water relations of FFV for packaging design, as well as, an overview of models reported in literature

Advances in non-destructive early assessment of fruit ripeness towards defining optimal time of harvest and yield prediction—a review

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Global food security for the increasing world population not only requires increased sustainable production of food but a significant reduction in pre-and post-harvest waste. The timing of when a fruit is harvested is critical for reducing waste along the supply chain and increasing fruit quality for consumers. The early in-field assessment of fruit ripeness and prediction of the harvest date and yield by non-destructive technologies have the potential to revolutionize farming practices and enable the consumer to eat the tastiest and freshest fruit possible. A variety of non-destructive techniques have been applied to estimate the ripeness or maturity but not all of them are applicable for in situ (field or glasshousassessment. This review focuses on the non-destructive methods which are promising for, or have already been applied to, the pre-harvest in-field measurements including colorimetry, visible imaging, spectroscopy and spectroscopic imaging. Machine learning and regression models used in assessing ripeness are also discussed

Hyperspectral Imaging Coupled with Multivariate Analysis and Image Processing for Detection and Visualisation of Colour in Cooked Sausages Stuffed in Different Modified Casings

A hyperspectral imaging system was for the first time exploited to estimate the core colour of sausages stuffed in natural hog casings or in two hog casings treated with solutions containing surfactants and lactic acid in slush salt. Yellowness of sausages stuffed in natural hog casings (control group, 20.26 ± 4.81) was significantly higher than that of sausages stuffed in casings modified by submersion for 90 min in a solution containing 1:30 (w/w) soy lecithin:distilled water, 2.5% wt. soy oil, and 21 mL lactic acid per kg NaCl (17.66 ± 2.89) (p < 0.05). When predicting the lightness and redness of the sausage core, a partial least squares regression model developed from spectra pre-treated with a second derivative showed calibration coefficients of determination (Rc2) of 0.73 and 0.76, respectively. Ten, ten, and seven wavelengths were selected as the important optimal wavelengths for lightness, redness, and yellowness, respectively. Those wavelengths provide meaningful information for developing a simple, cost-effective multispectral system to rapidly differentiate sausages based on their core colour. According to the canonical discriminant analysis, lightness possessed the highest discriminant power with which to differentiate sausages stuffed in different casings.Japan Society for the Promotion of Science P16104, 16F16104, 20K1547

Influence of Drying Techniques on Tomato Flavour

This thesis researched the best possible operating conditions of a test dryer and the mild drying technique for preserving fresh tomato flavour. Fresh flavour is the one with more green notes and less heat-induced notes. Three different type of test dryers, namely a convective dryer (Heat Pump Dehumidifier, HPD), a conduction and infra-red radiation dryer (Refractance Window Dryer, RWD), and a microwave radiation dryer (Microwave Vacuum Dryer, MWVD) were chosen as a representative of differing principles of heat transfer. Control dryers based on commercial tomato products were also chosen, the freeze dryer (FD), spray dryer (SPD) as a basis for comparison of the flavour quality. A thin layer model was developed to predict the drying behaviour of tomato pulp and energy modelling was used with the RWD. For the RWD, conduction and evaporation were proved to be the dominant mechanisms of heat gain and heat loss from the product, respectively. The radiation effect was found to be negligible, so disproving the concept of RWD. With the HPD, a preliminary lipoxygenase inactivation model was employed to understand the low temperature drying effect on the flavour producing enzyme. Volatile and non-volatile flavour measurements were carried out for all the test dried samples. FD and HPD- dried tomatoes of the same cultivar were not significantly different from each other. Generally, acid concentration increased while sugar concentration decreased with increased thermal processing. Microwave vacuum drying operated under high vacuum of 0.1 mbar (also called as microwave freeze drying) produced the best flavour quality, followed by HPD. An integrated approach of instrumental and sensory analysis was adopted to investigate the drying impact on the stability of flavour compounds and their associated sensory attributes. The volatile and sensory profiles of HPD- and FD-dried tomatoes were comparable, whereas loss of compounds contributing to fresh green aroma and presence of heat-induced compounds contributing to a cooked aroma were detected in the SPD-dried tomatoes and paste. Volatiles were found to be a good marker than non-volatiles. They were highly significant for discriminating the sensory attributes of processed tomatoes, allowing a better insight into the development of mild drying techniques

Development of a solar powered indirect air cooling combined with direct evaporative cooling system for storage of fruits and vegetables in Sub-Saharan Africa.

Doctoral Degrees. University of KwaZulu-Natal, Durban.Abstract available in PDF

Plant Essential Oil with Biological Activity

Plant essential oils (PEOs) are hydrophobic liquids that contain volatile chemical components that are derived from various plant parts. They are among the most important plant natural products because of their diverse biological features as well as their therapeutic and nutritional applications. In addition, several aromatic PEOs are used to flavor food and add aromas to incense in the culinary sector. Recently, many PEOs have demonstrated promising antimicrobial activity against different post-harvest diseases and have been considered as possible natural alternatives for chemical treatments. This Special Issue titled “Plant Essential Oil with Biological Activity” provided an overview of several elements of PEOs, including their biological applications, antimicrobial activities, bio-pharmaceutical properties, principal single constituents, and mechanisms of action. This Special Issues fills in knowledge gaps and aids in the advancement of EO applications around the world. This issue contains thirteen research articles and two review papers that address a wide range of topics and applications relevant to the bioactivity of PEOs