Developing postharvest management techniques using environmentally friendly and non-chemical approaches is key to extending the shelf life of avocados in a safer and health conscious manner. Avocados are prone to postharvest deterioration caused by mechanical damage, chilling injury, soft landing, uneven ripening and decay. Among the different cultivars of avocados commercially grown worldwide, the ‘Hass’ variety continues to be the most predominant due to its nutty flavour and functional properties. Most of the literature on postharvest decay and disorders affecting avocado fruit quality during storage and marketing is dedicated to the Hass avocado. Some of these postharvest problems are unique to the ‘Hass’ avocado can possibly be controlled by simply investing more research into other cultivars. These postharvest losses can be significantly controlled using eco-friendly technologies, such as modified atmosphere, physical heat treatments and most importantly investing in natural biodegradable products with naturally inherent antimicrobial properties. Thus, this review includes the recent research-based information on the use of non-chemical treatments on the improvement of fruit health and quality.

The ability of light-emitting diode (LED) light treatment to reduce the anthracnose decay via its eliciting effects and thus induce resistance in the avocado (Persea americana), was investigated in this study to replace the current postharvest fungicide treatment. In experiment 1, the effect of blue or red LED lights (6 h per day) on the incidence of anthracnose in artificially inoculated (Colletotrichum gloesposorioides) and naturally infected avocados (cv. Fuerte and Hass) at 12–14 °C (simulated market shelf) for 4, 8, 14, and 16 days was investigated. In experiment 2, the effect of blue or red LED lights on the induced defence mechanism, fruit metabolites, antioxidant activity, and percentage of fruit reaching ready-to-eat stage was determined. Exposure to red LED light significantly reduced the anthracnose decay incidence in naturally infected cv. Fuerte on day 12 and in cv. Hass on day 16 compared to the prochloraz fungicide treatment by upregulating the PAL genes and maintaining the epicatechin content. Blue LED light accelerated the ripening in both cultivars, probably due to reduced D-mannoheptulose content. Red LED light exposure for 6 h per day and 12 days storage showed potential to replace the prochloraz treatment with improved ascorbic acid content and antioxidant activity.

Okra (Abelmoschus esculentus) is an important vegetable that has been indigenized in African countries where it is consumed as a relish. There is still, however, a lack of documented cultivation techniques for better yields. An organic medium-enclosed trough (OMET) system is a growing technique that has been developed to reduce water and nutrient seepage during plant production. The study objectives evaluated the effect of OMET on the growth, yield, and nutritional attributes of okra. A complete randomized block design was established to accommodate the two treatments: OMET and non-OMET, in a micro-plot under field conditions. The stem diameter and plant height were recorded weekly during plant growth, and a clear increasing trend in OMET over non-OMET was observed from week 4 of transplantation. The OMET growing technique significantly increased the stem diameter and plant height by 37 and 48%, respectively. When evaluating the yield attributes, a similar trend was observed, where the OMET system significantly increased the yield attributes of okra as follows: biomass by 50%, the number of branches by 50%, the number of pods per plant by 49%, fresh pod weight by 53%, and pod length by 51%, while there was no significant difference in pod diameter width. Non-essential amino acids compounds, including arginine, serine, glycine, aspartate acid, glutamic acid, alanine, and proline and essential amino acids, including histidine, threonine, methionine, lysine, tyrosine, leucine, phenylalanine, asparagine and glutamine, were highly maintained in OMET compared to non-OMET. OMET enhanced the upregulation of proteins, Ca, Mg, K, Mn, Na, P and Zn elemental nutrients in the disposal of less irrigation water than non-OMET. This growing technique could be recommended for small-scale and commercial farming to improve the okra production of nutrition.

Organic Medium Enclosed Trough (OMET) system is a new non-drainable growing technique. The study set out to investigate the interactive effects of OMET and Amaranth species variation on some growth attributes, yield, bioactive compounds, and nutrients. Three Amaranth species, A. caudatus, A. cruentus, and A. tricolor, were grown in OMET and non-OMET growing conditions. Growth attributes, irrigation water, bioactive compounds, and nutrients were determined. Non-OMET growing conditions and A. cruentus showed the highest total phenolics and flavonols followed by A. caudatus and A. tricolor, whilst tannins were predominant in A. caudatus followed by A. cruentus and A. tricolor. The use of unsupervised PCA showed major metabolic variation based on Amaranth species and the use of supervised OPLS-DA showed clear metabolic variation based on OMET and non-OMET. OMET and A. cruentus showed the highest plant height, stem diameter, biomass, and some nutrients (%protein, Ca, P, Cu, Se, Zn), followed by A. caudatus based only on growth and biomass, and A. tricolor based only on some nutrients (Mg, K, Mn, and Fe). The use of the OMET system on A. cruentus and A. tricolor can be recommended to mitigate climate change effects on nutritional composition using relatively low levels of irrigation water.

Organic Medium Enclosed Trough (OMET) is a new non-drainable growing technique. The study envisioned to investigate the interactive effects of OMET and Amaranth species vari-ation on some growth attributes, bioactive compounds and nutrients. Three Amaranth species: A. caudatus, A. cruentus and A. tricolor were grown in an OMET and non-OMET growing conditions. Growth attributes, irrigation water, bioactive compounds and nutri-ents were determined. Non-OMET and A. cruentus showed the highest total phenolics and flavonols followed by A. caudatus and A. tricolor, whilst tannins were predominant in A. caudatus followed by A. cruentus and A. tricolor. The use of unsupervised PCA showed major metabolic variation based on Amaranth species and the use of supervised OPLS-DA showed clear metabolic variation based on OMET and non-OMET. OMET and A. cruentus showed the highest plant height, stem diameter, biomass, and some nutrients (%protein, Ca, P, Cu, Se, Zn), followed by A. caudatus based only on growth and biomass, and A. tricol-or based only on some nutrients (Mg, K, Mn, and Fe). The use OMET system on A. cruentus and A. tricolor can be recommended to mitigate climate change effects on nutritional com-position using low irrigation water.