No abstract

No abstract

This work was aimed to optimize an enzyme‐assisted aqueous procedure to extract oil from walnuts. Response surface methodology using Central Composite Design was applied to optimize operating conditions that affect the oil extraction process (time, temperature, and water:walnut flesh ratio). Extraction time and temperature did significantly affect extraction yield (R2 = 0.875) and oxidative stability index (OSI) (R2 = 0.531). The predictive capacity of the proposed mathematical surface equation for yield was experimentally tested and its suitability was confirmed under the optimal conditions (41.8°C, 88 min) resulting in 75.4% (experimental) versus 75% (theoretical). Two different experimental conditions were proposed for walnut oil extraction, taking into account the extraction yield and the OSI response surfaces. These walnut oils were compared to that extracted with hexane, resulting in higher quality in terms of OSI (5.27 and 5.12 hr vs. 1.51 hr) and total tocopherols content (685.5 and 575.4 mg/kg oil vs. 269.1 mg/kg oil). Practical applicationsThe purpose of this research was aimed to optimize the oil extraction from walnuts kernels using an enzyme‐assisted aqueous procedure. Consumers’ interest in walnut oil has noticeably grown due to its functional and nutritional properties. Response surface methodology is an adequate approach to establish the operation conditions of the extraction process. Temperature and time resulted to be the variables that significantly influenced the oil extraction yield, while the water:walnut flesh ratio did not have any significant effect. Two different oils were obtained using those experimental conditions that allowed maximizing the extraction yield and preserving oils oxidative stability. The walnut oils obtained by the proposed enzyme‐assisted aqueous extraction methods possessed higher quality than that extracted using organic solvent.

No abstract

Consumers demand traditional, tasty tomatoes in contrast to new hybrid cultivars that have poor sensory characteristics. Some physicochemical parameters (total soluble solids, pH, titratable acidity, color and firmness), functional properties (vitamin C, lycopene, β-carotene and total antioxidant activity) and sensory characteristics of five traditional tomato varieties (T1-T5) in three ripening stages, grown under organic conditions, were evaluated. These were compared to the commercial hybrid ‘Baghera’, grown in the same conditions. Firmness of all varieties declined and the color parameters L* and H* decreased, whereas a* and a*/b* increased progressively with ripening. Lycopene also increased with ripening in all varieties, with the highest content being 132.64 mg kg−1 fw for T4. All traditional tomato varieties were richer in lycopene than commercial ones in the two last ripening stages. Vitamin C content ranged widely between 27.33 and 267.27 mg kg−1 fw. Among the traditional varieties, T2 (BGV003524) stood out due to its highest total soluble solids and vitamin C contents, total antioxidant activity, and H* and a*/b*; this variety was also the most appreciated by panelists. These traditional varieties could be an alternative to commercial cultivars, as they have good quality characteristics and can satisfy consumer demand for organic produce.

No abstract

Melatonin (N-acetyl-5-methoxytryptamine) is involved in multiple functions in plants. However, its role in some metabolic pathways and exogenous application’s effect on fruits is still unclear. Furthermore, the effects of pre-storage melatonin treatment on sensory traits and consumer acceptance of cherries have yet to be studied. For this reason, the early sweet cherry cultivar ‘Samba’ harvested at the commercial ripening stage was treated with different melatonin concentrations (0.1, 0.3, and 0.5 mmol L−1) and stored for 21 days under controlled cold temperature and humidity. The standard quality, respiration rate, postharvest aptitude, sensory quality, phenols, and antioxidant systems (non-enzymatic and enzymatic) were analysed at 14 and 21 days of storage. Postharvest treatment with melatonin 0.5 mmol L−1 improved firmness and reduced weight loss and non-commercial fruit percentage while increasing respiration rate, lipophilic antioxidant activity, and ascorbate peroxidase enzyme activity. Furthermore, the treated cherries showed better sensory qualities, such as uniformity of colour and skin colour, as well as being sourer and showing better consumer acceptance and liking after 14 days of storage. Therefore, we conclude that the 0.5 mmol L−1 concentration is effective on the standard, sensory, and bioactive quality of early sweet cherries and can be considered an eco-friendly tool for maintaining the postharvest quality of early cherries.

The objective of this study was to evaluate the fruit development, the quality at harvest and the shelf-life changes of three apricot cultivars—‘Spring Blush’, ‘Robada’, and ‘Kioto’—produced in the conditions of the Southwest Iberian Peninsula. Pomological characteristics and global quality (colour, firmness, total soluble solids, and total acidity) were weekly evaluated during fruit growth and ripening. Apricots were harvested at commercial ripening, and six and three days before, were tested for each harvest on the harvesting day and after three and five days of shelf-life at 20 °C, evaluating chlorophyll and carotenoids content and sensory quality. ‘Spring Blush’ was the earliest cultivar with a small calibre, and the change in colour was found to depend more on the evolution during the shelf-life than on the harvest date; although the panellists rated it well, it presented a significant lack of firmness for successful marketing. ‘Robada’ was the cultivar with the lowest evolution of colour, sugar and acid content, and it was the worst valued by tasters. In ‘Kioto’, differences in soluble solids, acidity, and colour were of high importance in the last days of development on the tree. ‘Kioto’ was the cultivar that showed the largest fruit size and colouring during the ripening on the tree, as well as the one with the highest overall quality that improves during shelf-life.