Department of Chemical Engineering, Jadavpur University, Kolkata, India.
J Sci Food Agric. 2021 Jul;101(9):3564-3574. doi: 10.1002/jsfa.10983. Epub 2020 Dec 25.
Granny Smith (GS) apple has low protein content and poor antimicrobial properties; hence it has been blended with Aloe vera (AV; high ascorbic acid, antimicrobial and antioxidant properties) and soybean flour (SF; rich in phenols, flavonoids, ascorbic acid, total antioxidant and protein) in different proportions to obtain fortified GS, i.e. GSAVSF. Moreover, GS being a perishable fruit, its moisture content should be reduced to enhance shelf life. Accordingly, this GSAVSF was osmotically pre-dehydrated and finally dried through energy-efficient quartz-halogen radiation (QHR) assisted vacuum-drying (QHRVD) to produce dried GSAVSF i.e. (DGSAVSF) under optimized conditions.
The optimally dehydrated DGSAVSF product resulted in minimum moisture (4.85% w/w) and maximum protein (6.24 g kg ) content. The application of osmotic dehydration and QHRVD afforded acceptable colour of DGSAVSF compared to GSAVSF (ΔE * = 10.07 ± 0.21). A parametric drying model was formulated that corroborated well with Fick's equation. QHRVD rendered high moisture diffusivity (1.49 × 10 m s ) and low activation energy (27.64 kJ mol K ). Appreciable quality improvements with respect to fresh GS concerning ascorbic acid (176.05%), total phenolic (579.07%), total flavonoid (333.33%) contents and 2,2'-diphenyl-1-picrylhydrazyl radical scavenging activity (446.71%) could be achieved. The product demonstrated satisfactory shelf life (1 × 10 CFU g : aerobic mesophilic; 1 × 10 CFU g : mould and yeast) and high rehydration ratio (4.25 ± 0.1).
The enrichment of GS with AV and SF along with optimal drying protocols could provide a quality fortified DGSAVSF through an energy-proficient sustainable process. The highly nutritious product with suitable colour, microbial stability and rehydration ratio also satisfied a 9-point hedonic scale, thus confirming consumer acceptability. © 2020 Society of Chemical Industry.
青苹果（GS）的蛋白质含量低，抗菌性能差；因此，它与库拉索芦荟（AV；富含抗坏血酸、抗菌和抗氧化特性）和大豆粉（SF；富含酚类、类黄酮、抗坏血酸、总抗氧化剂和蛋白质）按不同比例混合，以获得强化 GS，即 GSAVSF。此外，GS 是一种易腐水果，应降低其水分含量以延长保质期。因此，通过渗透脱水和节能石英-卤素辐射（QHR）辅助真空干燥（QHRVD）对这种 GSAVSF 进行预干燥，在优化条件下生产出干燥的 GSAVSF，即（DGSAVSF）。
最佳脱水的 DGSAVSF 产品的水分含量最低（4.85%w/w），蛋白质含量最高（6.24g/kg）。与 GSAVSF 相比，渗透脱水和 QHRVD 使 DGSAVSF 的颜色可接受（ΔE *= 10.07 ± 0.21）。制定了一个参数干燥模型，该模型与菲克方程吻合良好。QHRVD 使水分扩散系数高（1.49×10 m s），活化能低（27.64kJ/mol·K）。与新鲜 GS 相比，DGSAVSF 的抗坏血酸（176.05%）、总酚（579.07%）、总类黄酮（333.33%）含量和 2,2'-二苯基-1-苦基肼自由基清除活性（446.71%）均有显著提高。该产品的保质期令人满意（需氧嗜温菌为 1×10 CFU/g，霉菌和酵母为 1×10 CFU/g），再水合率高（4.25±0.1）。
通过添加 AV 和 SF 并结合最佳干燥方案，GS 可以通过节能可持续的工艺得到强化。该高营养产品具有合适的颜色、微生物稳定性和再水合率，还满足 9 分愉悦感量表，从而确认了消费者的可接受性。 © 2020 英国化学学会。
