Food Science and Technology International

The aim of this work was to determine storage capacity and changes in quality and consumer acceptance in plum harvested at different dates as well as to determine which instrumental parameters show good correlation with consumer acceptance and sensory properties. Both harvest date and storage time played a significant role in quality and sensory characteristics. Incidence of internal breakdown (IB) was significantly higher in fruit harvested last and increased significantly until the end of storage. Market life of ‘Green Gage’ plum varies from 20 days in fruit harvested on the last harvest date to 40 days in fruit harvested on earlier dates. When storage is needed, firmness, the best harvest index, should be higher than 42 N in order to extend market life and prevent IB damages in ‘Green Gage’ plums. However, fruit from early harvest dates has a lower consumer acceptance than fruit from late harvest dates (low TSS:TA). Thus, a minimum quality threshold based on TSS:TA (18.9) has been established over which consumer liking for European plums cv. Green Gage improves significantly. High linear regression between a* and TSS:TA would allow to use the a* color parameter as a nondestructive measurement to estimate consumer acceptance.

In this article 11 commercial sweet cherry cultivars were selected to evaluate sensory, nutritive and functional properties over the maturation process on tree. Fruit quality was significantly different among cultivars and maturity stages at harvest, with the highest quality scores being found in the harvest which was 4 days beyond current commercial harvest maturity for all the cultivars tested. Taking into account all of the measured parameters (weight, firmness, color, acidity and total soluble solids), ‘NY-6479’, ‘Prime Giant’ and ‘Sunburst’ could be classified as having the highest quality in terms of sensory attributes. However, ‘Cristalina’ and ‘Sonata’ had the highest functional quality, as determined by the measurement of bioactive compound content and antioxidant capacity. We conclude that a delay of a few days in harvesting of sweet cherries would lead to achieve maximal nutritional (highest sugar and organic acid contents), sensory (greatest firmness and color development) and functional (greatest phenolics content, anthocyanins and antioxidant capacity) quality to provide both eating enjoyment and health benefits to the consumer.

Tannase was effectively immobilized on alginate by the method of crosslinking-entrapment-crosslinking with a high activity recovery of 76.6%. The properties of immobilized tannase were investigated. Its optimum temperature was determined to be 35 ^° C, decreasing 10 ^°C compared with that of free enzyme, whereas the optimum pH of 5.0 did not change. The thermal and pH stabilities of immobilized tannase increased to some degree. The kinetic parameter, Km, for immobilized tannase was estimated to be 11.6 × 10^-4 mol/L. Fe²⁺ and Mn²⁺ could activate the activity of immobilized tannase. The immobilized tannase was also applied to treat the tea beverage to investigate its haze-removing effect. The content of non-estern catechins in green tea, black tea and oolong tea increased by 52.17%, 12.94% and 8.83%, respectively. The content of estern catechins in green tea, oolong tea and black tea decreased by 20.0%, 16.68% and 5.04%, respectively. The anti-sediment effect of green tea infusion treated with immobilized tannase was significantly increased. The storage stability and reusability of the immobilized tannase were improved greatly, with 72.5% activity retention after stored for 42 days and 86.9% residual activity after repeatedly used for 30 times.

Fish bones are important sources of collagen and are usually discarded by the processing industries. A response surface methodology was utilized to optimize the extraction process of gelatin from king weakfish (Macrodon ancylodon) bones submitted to alkali pre-treatment. The experimental responses were gel strength and gelatin yield, while the studied variables were sodium hydroxide concentration (2 and 4 g/100 g), maceration time (48 and 72 h) and extraction temperature (60 °C and 80 °C). An increase in extraction temperature carried out a significant (p ≤ 0.05) reduction in gelatin gel strength. The increase in the NaOH concentration during maceration increased the process yield. Extraction temperature, NaOH concentration and their interaction had a pronounced effect on process yield. High extraction temperatures resulted in higher yields, but reduced the strength of gelatin gel.

Twenty castrated male Iberian pigs were divided into two groups of 10 pigs each according to the experimental diet received daily during the fattening period in confinement (acorn fed ad libitum or 4 kg of a formulated diet rich in C18:1 n—9). Dietary effects on performance, carcass characteristics and backfat, intramuscular, and liver fatty acid composition were assessed. Pigs fed only with acorns ate less, leading to a lower growth performance and carcass quality than pigs fed the formulated diet. Pigs fed acorns had lower C16:0 proportions in outer, inner, and subinner subcutaneous backfat layers. The C18:1 n—9 proportions in the inner and subinner subcutaneous backfat layers were higher in pigs fed acorns than in those fed the formulated diet. Pigs fed acorns had higher C18:2 n—6 proportion than those fed the formulated diet in outer subcutaneous backfat layer. The diet did not affect outer, inner, and subinner subcutaneous backfat melting points. Except a higher C18:0 in intramuscular fat polar lipids and higher C16:1 n—9 in the liver polar lipid fraction in pigs fed acorns, the diet had no significant effect on intramuscular and liver fatty acid composition.

Various food by-products were incorporated into rice grits and submitted to extrusion cooking to produce fortified extruded food products. The blends of various formulations of durum clear flour (8—20%), partially defatted hazelnut flour (PDHF) (5—15%), fruit waste blend (3—7%) and rice grits were extruded using single screw extruder. Response surface methodology was used to evaluate the effects of process variables, namely the feed moisture content (12—18%), barrel temperature (150—175 °C) and screw speed (200—280 rpm), and change in feed composition on total phenolic content, antioxidant activity, percent starch gelatinization and starch digestibility of the extrudates. Extrusion cooking process significantly increased the level of phenolic compounds and starch digestibility of extruded products. Increasing PDHF and fruit waste content caused increase in total phenolic content and antioxidant activity of the extruded samples, whereas percent starch gelatinization and digestibility values decreased. Moisture content and temperature significantly influenced the total phenolic content, antioxidant activity, percent starch gelatinization and starch digestibility values. In extruded samples, positive correlations were determined between antioxidant activity and total phenolic matter and percent starch gelatinization and the starch digestibility values, respectively.

This study is a contribution to valorise date palm sap (Phoenix dactylifera L.) by elaboration of high quality syrup. Sap was concentrated by evaporation and the obtained product was characterized by its physicochemical, rheological, thermal, sensory properties and by its antioxidant activity. Syrups from date palm sap have a good nutritional value marked by high amounts of sugars (58—75 g/100 g fresh matter basis), minerals (2.1—2.6 g/100 g fresh matter basis) and phenolics (147.61—224.55 mg of ferulic acid equivalents/kg fresh weight). Syrup also presents an antioxidant activity that appears related to total phenolic content. Rheological properties indicate that syrup preserves a Newtonian behavior from 10 ^°C to 55 ^°C well modeled by Arrhenius equation. Hedonic evaluation showed that consumers’ appreciation of date palm syrup was not significantly different to the most known sap syrup: maple syrup.