Sensory, physicochemical, and functional stability of freeze-dried blackcurrant (Ribes nigrum L.) Snacks. Effect of sweeteners.

The objective of this work was to develop two freeze-dried snacks from blackcurrant and different sweeteners: honey/isomalt (HI) sweetened with honey/isomalt, and isomalt/stevia (IS) sweetened with isomalt/stevia. Both snacks showed high bioactive compounds retention (>75%) and no significant changes in several physicochemical properties after 6 months storage. Fresh snacks were hard and crunchy, and the perception of consumers within liking categories was: HI: 43%, and IS: 72%. After storage HI snack showed higher acceptance by consumers (75% within liking categories) while IS snack showed a decrease in their acceptance (63% within disliking categories). The penalty analysis showed that the sensory shelf-life of both snacks would be limited by the changes produced in texture and color during storage. HI snack could reach six storage months, while IS would be stored up to 3 months. The use of diverse sweeteners allowed obtaining two different products which could be incorporated into a healthy diet.

Different methods for textural evaluation of freeze-dried candies during storage.

The textural changes during storage of two freeze-dried candies developed from blackcurrant fruits, unflavored yogurt, and different alternative sweeteners, one sweetened with honey/isomalt (HI) and another sweetened with isomalt/stevia (IS), were analyzed using three different methods (instrumental, sensory, and image analysis). Fresh candies were in the supercooled state and presented different structural and textural characteristics (HI: compact and homogeneous, and IS: porous and crunchy), with Fmax values of 139 ± 14 and 174 ± 16 N for HI and IS, respectively. After storage, the instrumental analysis showed approximately 60% average drop in Fmax and W values, in agreement with the decrease observed by sensory analysis in hardness, fracturability, and crispness. Image analysis showed an increase in parameters related to the homogeneity and the uniformity/smoothness for HI. Pearson's correlation coefficients analysis showed that there was a good correlation between the three techniques used, suggesting that the joint use of these methods could be performed for a better understanding of complex food texture.

Development of healthy gummy jellies containing honey and propolis.

BACKGROUND: The objective of this work was to develop gummy jellies containing honey and propolis, keeping the natural antioxidant principles of the beehive ingredients and satisfying consumer requirements. RESULTS: A gummy jelly containing honey and propolis (HPGJ) was developed. A sensory study with consumers (n = 74) performed an intensity level evaluation test analyzing color, hardness, adhesiveness, gumminess, sweet taste and honey taste. A penalty analysis indicated that HPGJ was too hard. However, in the global acceptance study, more than 90% of consumers gave liking categories. Regarding the potential functional properties, the antioxidant capacity (AC) of HPGJ was 8.17 ± 0.55 mmol Trolox equivalent kg-1 , and up to 40% AC was retained after in vitro digestion. Additionally, AC of HPGJ was up to ten times higher than that of similar commercial products. A storage study at 25 °C showed that color and AC increased significantly over 90 days owing to the development of Maillard reaction. Storage under darkness allowed keeping low values of global color change for up to 45 days. Another positive facet was that the addition of propolis delayed fungal growth during storage. CONCLUSION: An organoleptically palatable gummy jelly was obtained. Among the positive features, it showed higher AC than similar commercial candies. Additionally, HPGJ offered a high bioaccesible AC input detected upon in vitro digestion. Overall, HPGJ could be considered an interesting, appetizing and healthier alternative to regular gummy jellies available in the market. Adequate packaging should be considered in order to extend HPGJ shelf life, reducing browning reactions. © 2019 Society of Chemical Industry.

Physical and functional properties of spray-dried powders from blackcurrant juice and extracts obtained from the waste of juice processing.

Blackcurrants contain high levels of polyphenolics, particularly flavonols and anthocyanins, which contribute to their high antioxidant activity. The aims of this work were the recovery of bioactive compounds from the remaining solid (waste) after processing blackcurrant juice and to obtain spray-dried powders from the blackcurrant juice and extracts. The extraction of bioactive compounds from the fruit pulp was performed by ultrasound-assisted extraction. Experiments were conducted to select the more suitable solvent, and citric acid was chosen. Then, to optimize the extraction conditions (time, solvent concentration, and amplitude) an experimental design using a Box-Behnken Design was done. Comparing the optimized extract with the fruit, 31% total monomeric anthocyanins, 19% total phenolic compounds, and 10% antioxidant capacity were obtained. The optimized extract and the juice were mixed and spray dried, using maltodextrin as carrier matrix. A blackcurrant powder with low hygroscopicity 14.46 ± 0.13 (g a.w./100 g d.m) and high solubility 94.25 ± 4% was obtained. High concentration of bioactive compounds and antioxidant capacity was recorded: Total monomeric anthocyanins 63.01 ± 1 (mg cyn-3-glu/100 g.d.m), total phenolic content 116.87 ± 5 (mg gallic acid/100 g d.m.), and antioxidant capacity 144.40 ± 0.11 (mg eq Trolox/100 g.d.m.).