No abstract

No abstract

No abstract

No abstract

Soursop fruit (Annona muricata L.) production is diminished by the attack of pathogens such as Nectria haematococca. However, the fruit–pathogen interaction at the biochemical and molecular levels is still unknown. The objective of this study was to analyze the response of the soursop fruit to the presence of N. haematococca during postharvest storage. Soursop fruits were inoculated with the pathogen and total phenolic compounds, antioxidant capacity by Ferric reducing/antioxidant power (FRAP), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS•+), and 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH•), as well as enzymatic activity and transcript levels of polyphenol oxidase (PPO) and superoxide dismutase (SOD), were evaluated at 1, 3, and 5 days of storage. The noninoculated fruits were the controls of the experiment. The highest total phenol content was recorded on day one in the inoculated fruits. FRAP, ABTS, and DPPH activity presented the highest values on day three in the control fruits. Inoculated fruits recorded the highest PPO activity on day five and a five-fold induction in the PPO transcript on day three. SOD activity showed a decrease during the days of storage and 10-fold induction of SOD transcript on day three in the inoculated fruits. Principal component analysis showed that total phenols were the variable that contributed the most to the observed variations. Furthermore, a positive correlation between total phenols and SOD activity, PPO expression, and SOD expression, as well as between DPPH and FRAP, was recorded. The results showed a differential response in antioxidant capacity, enzymatic activity, and gene expression during the interaction of soursop fruits–N. haematococca at postharvest storage.

Edible coatings based on 2% starch (w/v) extracted from tropical fruits were applied on stenospermocarpic mango fruits with the objective to prolong its shelf life during storage and give them an added value since they have no commercial value. In this regard, stenospermocarpic mangoes were coated with starch from banana “Pear” (T1 and T2), starch from soursop (T3 and T4), and starch from stenospermocarpic mango (T5 and T6), and two uncoated control treatments (T7 and T8). The fruit of T1, T3, T5, and T7 treatments were stored for 15 days (10 days at 10 ± 2°C and then at 22 ± 2°C for 5 days). The fruit of T2, T4, T6, and T8 treatments were stored for 10 days at 22 ± 2°C. Data were analyzed with a 4×2 factorial experimental design. Weight loss (g), firmness (N), total soluble solids content (%), titratable acidity (%), and color (L∗h∗C∗) were evaluated. The fruit coated with mango starch (T5) showed less weight loss (2.57%), greater firmness (18.6 N), as well as a high content of TSS (28.76%) compared with the control. The T5 extended the shelf life of the fruit up to 15 days (10 days at 10 ± 2°C and 5 days at 22 ± 2°C).

Fruit and vegetable products are susceptible to the attack of fungi during postharvest handling. Chemical fungicides are the most commonly used technique to control fungal diseases. However, an alternative product is the use of plant extracts, which have been reported in in vitro and in vivo conditions. The objective of this investigation was to identify one of the main pathogens of mango and soursop fruits using morphological and molecular tools as well as to evaluate the in vitro inhibitory effect of papaya and soursop leaf and seed extracts. Two pathogens were isolated and identified by their morphological and molecular characteristics from mango and soursop fruits. We obtained extracts from leaves and seeds of soursop and papaya using five solvents of increasing polarity (hexane, acetone, ethanol, methanol, and water) through the ultrasound-assisted extraction technique at a frequency of 35 kHz and 160 W for 14 min. In vitro evaluations of the extracts were performed using the Kirby–Bauer technique. The extracts with the highest percentage of inhibition were analyzed qualitatively and quantitatively using standardized techniques of colorimetry and spectrophotometry. Furthermore, we determined the content of total phenols, flavonoids, alkaloids, terpenoids, anthraquinones, coumarins, and saponins. As a result, we identified the pathogens as Colletotrichum fructicola and Nectria haematococca. Aqueous extracts (water as a solvent) showed a higher percentage of inhibition of both pathogens compared with the other extracts. Furthermore, the aqueous extract of papaya leaf was the most effective among all extracts. The aqueous papaya leaf extract exhibited a percentage of inhibition of 49.86% for C. fructicola and 47.89% for N. haematococca. The aqueous extracts of papaya leaf and seed (AqEPL and AqEPS) presented the greatest amount of metabolites (except anthraquinones and coumarins). The aqueous soursop leaf extract (AqESL) presented the greatest amount of phenols, tannins, and flavonoids (219.14 ± 8.52 mg GAE/L, 159.84 ± 10 mg GAE/g dm and 0.13 ± 1.12 × 10−4, respectively). The aqueous soursop seed extract (AqESS) had the highest saponin content with 1.2 ± 0.1 mg QSES/g dm and the papaya leaf accusative extract (AqEPL) had the highest alkaloid content (6.413 ± 1 × 10−3 mg AE/g dm) compared with the other extracts. The AqESS had a lower content of secondary metabolites (sterols, alkaloids, and saponins), while AqESL showed no presence of alkaloids and coumarins.

No abstract