Search Results (4)

The quality of sweet orange (Citrus sinensis L.) is determined by the presence of decay caused by phytopathogenic fungi. This can develop in the field and rapidly spread among oranges during postharvest storage. Currently, the conventional treatments applied to control this problem are chemical fungicides. However, consumers demand eco-friendly and non-polluting alternatives with low chemical residues. Therefore, the aim of this work is the preharvest application of sodium bicarbonate (SB) and potassium silicate (PS) solutions at 0.1 and 1% to Navel and Valencia oranges to elucidate the effect on fruit quality and fungal decay at harvest and after 42 days of storage at 8 °C. Results showed that oranges treated with SB 0.1%, PS 0.1, and PS 1% maintained quality traits at similar levels to the control ones. However, SB 1% reduced firmness and increased weight loss, respiration rate, maturity index, and citrus color index. The total carotenoid content significantly increased in oranges treated with SB 1%, and no differences were observed in the other treatments compared to the control. Total antioxidant activity and total phenolic content decreased in oranges treated with SB at 0.1 and 1%, contrary to the results observed in oranges treated with PS, where both parameters increased. Regarding fungal decay, the best results were obtained in oranges treated with the highest doses of SB and PS. Therefore, the use of SB and PS in preharvest sprays could be an alternative to control fungal decay without affecting orange quality. Full article

Three yeast strains, namely Cryptococcus albidus (Ca63), Cryptococcus albidus (Ca64), and Candida parapsilosis (Yett1006), and their combinations, including single yeast agent, two combined yeast strains, single yeast agent + NaHCO₃, single yeast agent + chitosan, single yeast agent + ascorbic acid, and single yeast agent + konjac powder, were evaluated for their activity against Botrytis cinerea, the most economically important fungal pathogens causing postharvest disease of snap beans. In in vitro tests, no inhibition zone was observed in dual cultures of three yeast strains and B. cinerea. The mycelial growth inhibition rates of B. cinerea for Ca63, Ca64, and Yett1006 were 97%, 95%, and 97%, respectively. In in vivo tests, the optimal combination of the lowest disease index of snap beans with B. cinerea was Ca63 + Ca64, with a preventing effect of 75%. The decay rate and rust spots index of Ca64 + ascorbic acid combination were 25% and 20%, respectively, which were the lowest. The activities of defense-related enzymes increased, while malondialdehyde (MDA) content was suppressed in snap beans after different treatments. Our results highlight the potential of the three yeast strains and their combinations as new nonpolluting agents for the integrated control of B. cinerea on snap beans. Full article

Pomegranate exhibits important postharvest quality losses that limit its storage potential, caused mainly by weight loss, chilling injury and fungal diseases. In this work, we evaluated the effect of novel hydroxypropyl methylcellulose (HPMC) edible coatings (ECs) formulated with three different lipids (beeswax (BW), carnauba wax, and glycerol monostearate), as hydrophobic components, and two different GRAS salts (potassium bicarbonate (PBC) and sodium benzoate (SB)), as antifungal ingredients, to control weight loss and natural fungal decay of ‘Mollar de Elche’ pomegranates during storage at 20 °C. Afterwards, selected antifungal ECs and commercial modified atmosphere packaging (MAP) films were assayed alone or in combination to control natural decay and preserve fruit quality of pomegranates stored at 5 °C for 4 months plus 1 week at 20 °C. Results showed that ECs amended with SB reduced pomegranate latent infections caused by Botrytis cinerea and wound diseases caused by Penicillium spp. Moreover, MAP technologies were confirmed as an efficient mean to preserve freshness, prevent fruit shriveling and rind browning, and reduce fungal decay, thus extending storage life of pomegranates. The combination HPMC-BW-SB + MAP was the most promising treatment as it reduced weight loss and decay, without negatively affecting the fruit physicochemical and sensory quality. Full article

The in vitro antifungal activity of various generally recognized as safe (GRAS) salts against Colletotrichum gloeosporioides, the causal agent of citrus postharvest anthracnose, was evaluated as mycelial growth reduction on potato dextrose agar (PDA) dishes amended with salt aqueous solutions at different concentrations. The most effective treatments [0.2% ammonium carbonate (AC), 2% potassium sorbate (PS), 0.2% potassium carbonate (PC), 0.1% sodium methylparaben (SMP), 0.1% sodium ethylparaben (SEP), 2% sodium benzoate (SB) and 2% potassium silicate (PSi)] were selected as antifungal ingredients of composite edible coatings formulated with hydroxypropyl methylcellulose (HPMC)-beeswax (BW) matrixes. Stable coatings containing these salts were applied in in vivo curative experiments to “Nadorcott” mandarins and “Valencia” oranges artificially inoculated with C. gloeosporioides and those containing 2% PS, 2% SB and 2% PSi were the most effective to reduce anthracnose severity with respect to control fruit (up to 70% on mandarins). The effect of these selected coatings on the quality of non-inoculated and cold-stored “Valencia” oranges was determined after 28 and 56 days at 5 °C and 90% RH, followed by 7 days of shelf life at 20 °C. None of the coatings significantly reduced weight loss of coated oranges, but they modified their internal atmosphere, increasing the CO₂ content. Overall, the coatings did not adversely affect the physicochemical and sensory attributes of the fruit. Full article