The quality of three dragon fruit clones ( Hylocereus spp.) was determined after x-ray irradiation for disinfestation of quarantine pests. Fruit were treated with irradiation doses of 0, 200, 400, 600, or 800 Gy and stored for 12 days at 10 °C. Irradiation did not affect soluble solids content, titratable acidity, or fructose concentrations. Glucose, sucrose, and total sugar concentrations decreased linearly as dose increased. Minimal softening occurred in the outer flesh layers for fruit treated with 400 or 600 Gy irradiation. Surface color, peel injury, and bract appearance differed among the three clones with irradiation stress, but in all cases, visible changes were minor. Fruit decay was absent or minimal, and disease ratings were not affected by irradiation. Irradiation treatment of dragon fruit at doses 800 Gy or less would ensure visual and compositional quality while providing quarantine security.

Listeria monocytogenes is a foodborne pathogen and causes illnesses with a high mortality rate in susceptible populations. Several dairy-related outbreaks have been attributed to contamination by L. monocytogenes, which requires antimicrobial interventions to enhance the safety of these products. This study aimed to determine the antimicrobial activity of the ohelo berry (Vaccinium calycinum), a Hawaiian wild relative of cranberry, against L. monocytogenes in culture media and milk products. The effect of ohelo berry juice at its sub-inhibitory concentrations on the physicochemical properties, biofilm formation, and gene expression of L. monocytogenes was also investigated. The minimum inhibitory concentration of ohelo berry juice against L. monocytogenes was 12.5%. The sub-inhibitory concentration of ohelo berry juice (6.25%) significantly increased the auto-aggregation and decreased the hydrophobicity, swimming motility, swarming motility, and biofilm formation capability of L. monocytogenes. The relative expression of genes for motility (flaA), biofilm formation and disinfectant resistance (sigB), invasion (iap), listeriolysin (hly), and phospholipase (plcA) was significantly downregulated in L. monocytogenes treated by the 6.25% juice. L. monocytogenes was significantly inhibited in whole and skim milk supplemented with 50% ohelo berry juice, regardless of the fat content. These findings highlight the potential of ohelo berry as a natural preservative and functional food to prevent L. monocytogenes infection.

Calcium (Ca) is a major plant nutrient that affects cell wall and plasma membrane formation and plays a key role in plant growth, biomass production, and function. Ca can be used to decrease fruit decay and increase firmness and shelf life. Different sources and concentrations of foliar-applied Ca were examined for the effects on nutrient concentration and growth of ‘Eksotika II’ papaya ( Carica papaya ) plants. Papaya seedlings were established in pots and irrigated with a standard nutrient solution in a net house. Four preharvest sprays were applied as foliar applications with three different sources of Ca {calcium chloride [CaCl ₂ ], calcium nitrate [Ca(NO ₃ ) ₂ ], and calcium propionate [Ca(C ₂ H ₅ COO) ₂ ]} at four concentrations (0, 60, 120, and 180 mg·L ⁻¹ ). Plant Ca concentration was unaffected by the different Ca sources. However, increased Ca concentration applied to the leaves enhanced plant accumulation of phosphorous and Ca in the plant, but decreased potassium (K) and magnesium (Mg) concentrations in the tissues. Plants that received Ca at 180 mg·L ⁻¹ had greater height and diameter than control plants. In a field trial with mature trees, preharvest applications of Ca (0, 4000, and 5400 mg·L ⁻¹ ) in the form of CaCl ₂ showed that increasing concentrations improved fruit Ca concentration, texture, and flavor; and decreased weight loss, Mg content, and apparent disease incidence of the fruit.

Beverage mixtures based on pineapple (Ananas comosus) and turmeric (Curcuma longa) juice as a ready-to-drink product were developed, and their physicochemical, nutritional, and sensory properties were evaluated. Four different concentrations of turmeric juice (5%, 10%, 15%, and 20% (v/v)) were added to pineapple juice to make turmeric-fortified pineapple (TFP) juice samples. Pineapple juice without turmeric was the control. The L*, a*, b*, titratable acidity (TA), total antioxidant capacity, and %DPPH scavenging values, as well as the concentrations of the phenolic compounds curcumin and demethoxycurcumin, were significantly increased with increasing turmeric concentration. Thirty volatile compounds were detected in the mixed juice samples with turmeric. Most of the turmeric-specific compounds, including monoterpenes, sesquiterpenes and turmerones, were detected in the TFP juice samples. While the antioxidant activity of the juice samples increased with increasing turmeric concentration, the pineapple juice fortified with 10% turmeric (10%T) had the best overall quality as determined by panelists. Greater concentrations of turmeric were associated with decreased palatability due to reduced mouthfeel and sweetness and increased aftertaste and sourness. These results suggest that the 10%T juice could be developed into a commercial functional beverage with increased overall flavor and nutritional quality.