Advances in Postharvest Packaging Systems of Fruits and Vegetable

The production of vegetables and fruits is at a high rate but the major challenging task is the postharvest handling and processing of the products. Approximately 20–30% of the production is being wasted due to a lack of proper postharvest management. Many developments were made to reduce this wastage such as cold chain development, different storage structures, some drying methodologies to promote the shelf life of produce. But all these systems need to be improved and utilized commercially. The losses still occur due to a lack of sound knowledge on the chemical nature of products and different management techniques (e.g., drying, cooling, blanching). Therefore, the successful design of the cooling, packing, storage transport, and drying processes of fresh food requires linking materials sciences, fluid dynamics, mechanical deformation, food chemistry, and process control.

The Current State of Knowledge about Essential Oil Fumigation for Quality of Crops during Postharvest

Prolonging crops’ shelf-life while retaining their high quality is a major issue related to postharvest management. During storage, fruits and vegetables are exposed to microbial attacks, which may cause spoilage. Crop deterioration causes the loss of physical properties and drops in quality and nutritional value. Hence, new techniques to improve the resistance of food products are being explored. One promising technique is fumigation. Essential oils and their constituents, due to their antimicrobial properties, are likely to be used as fumigants, as they are highly volatile, effective in low concentrations, biodegradable, and safe. Papers indicate that some of them can improve their quality by increasing the content of antioxidants. This comprehensive review aims to present the current state of knowledge about the influence of essential oil fumigation on crop quality. It covers antioxidant capacity, the content of some bioactive compounds, physicochemical properties, decay properties, and sensory attributes of fruits and vegetables treated with essential oil vapors. The review indicates that this technique might be an interesting field for further exploration due to the promising results presented in the studies. Moreover, the review presents major objectives for current studies and indicates a lack of recent papers in this field.

Smart post-harvest technology to maintain quality and safety in fresh produce supply chains

In this chapter the main challenges for the postharvest management of fresh produce are summarised. Key areas where the use of new smart technologies can improve crop management are explored, starting with how environmental sensors can be integrated into internet of things (IoT) systems with potential for use in the fresh produce supply chain. The next section summarises how the implementation of low oxygen storage environments is being refined through the use of dynamic controlled atmosphere systems incorporating sensor technologies. Modified atmosphere packaging and the developing field of active and intelligent packaging for fresh produce is then discussed. The chapter ends with future options for how smart technologies may develop in this sector.

Preharvest Foliar Salicylic Acid Sprays Reduce Cracking of Fig Fruit at Harvest

Peel cracking and ostiole-end splitting (collectively termed cracking) are common disorders in ripe fig fruit, downgrading fruit quality and thus limiting marketability. This two-year field study addressed the possibility of alleviating cracking at harvest by two foliar salicylic acid (SA) sprays prior to harvest (8 and 5 d). Three SA concentrations (0, 1, and 2 mM) were employed in the first year, and based on the obtained results two (0 and 2 mM) in the second year. A local variety (‘Vasilika’) with excellent organoleptic profile, and high sensitivity to cracking was evaluated. Fruit was harvested at commercial maturity. Fruit marketability was mainly based on the incidence and severity of cracking. Fruit weight, peel color, flesh total soluble solids (TSS), titratable acidity (TA), and pH were estimated for fig quality. The contents of total anthocyanins (TAN), cyanidin-3-rutinoside (c-3-rut; the major anthocyanin in fig), and the expression of four genes coding for regulatory enzymes (phenylalanine ammonia lyase, anthocyanidin synthase, UDP-flavonoid glucosyl transferase 1, and UDP-flavonoid glucosyl transferase 2) of the phenylpropanoid biosynthetic pathway were also determined in the peel. Preharvest SA application (2 mM) increased the percentage of fruit without cracking (sound fruit) by 1.4–2.6-fold, and of marketable fruit (sound and slightly cracked) by 2-fold. SA application (2 mM) was associated with increased flesh TSS and TA, as well as with decreased flesh pH and peel red coloration in stripe. The treatment (2 mM SA) decreased both TAN and c-3-rut contents, which were highly associated (r = 0.978). Responses of transcription level of the four genes to SA application varied, and did not correlate with the other variables in the study. In conclusion, SA appears to be a low-cost and environmentally-safe agent for improving fig fruit quality and marketability, and facilitates harvesting and postharvest management of figs.

Microencapsulation of Citral and its Antifungal Activity into Pectin Films

Citral is an essential oil with great antimicrobial activity, but its use in the food industry is limited due to its easy decomposition in room conditions. Therefore, this study aimed to microencapsulate citral by the spray drying process and incorporate the powder into pectin films to assess their antifungal activity. For this, solutions of maltodextrin (MD), Arabic gum (AG) sodium alginate (SA) at different concentrations were used to emulsify citral. The emulsion with 10:10:0.1 MD:AG:SA was selected to spray the drying process due to its small droplet size, monomodal size distribution, and low D[3,2], D[4,3], and span index. The dried powder had high solubility (83.4%), and low wettability time (27 s), moisture content (4.05%), and bulk density (0.72 g/cm3), allowing to infer powder stability and showing appropriate handling qualities on a large scale. Thermal analyses reveal that microparticles and pectin films provide thermal protection to citral from 37 to 175 °C. Concerning the antagonistic activity, pectin films added with citral microencapsulated had antifungal activity ranging from 42-68% against Penicillium italicum, Colletotrichum gloeosporioides, and Aspergillus niger under in vitro conditions. Therefore, these films serve as a basis for developing new edible coatings with practical applications in the postharvest management of phytopathogenic fungi.