Changes in qualities of minimally processed litchis: Effect of antibrowning agents, osmo-vacuum drying and moderate vacuum packaging

• Published in: Food science & technology Vol. 41; no. 4; pp. 660 - 668
• Main Authors: Shah, Narendra Singh, Nath, Nirankar
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2008; Elsevier
• Subjects: Antibrowning agents; ascorbic acid; Biological and medical sciences; brix; cysteine; drip loss; firmness; Food engineering; Food industries; food packaging; food preservation; food preservatives; food processing wastes; food storage; fresh-cut foods; Fruit and vegetable industries; fruit quality; fruits (food); Fundamental and applied biological sciences. Psychology; General aspects; Litchi chinensis; litchis; microbiological quality; Minimal processing; Moderate vacuum packaging; Osmo-vacuum dehydration; osmotic treatment; peeling; pericarp; phenolic compounds; physicochemical properties; resorcinol; sensory evaluation; storage temperature; storage time; sugar content; syrups; total solids; vacuum drying; vacuum packaging; waste utilization; water content; Litchi chinensis; Antibrowning agents; Minimal processing; Osmo-vacuum dehydration; Moderate vacuum packaging; Litchi; Fruit; Vacuum drying; Quality; Vacuum packaging; Conditioning; Dehydration
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2007.04.012

Litchi fruits (litchis) are highly susceptible to pericarp browning which lowers their commercial value even though the edible portion (aril) remains in excellent condition. Therefore, minimal processing of litchis was carried out. Litchis were peeled, destoned, and arils were treated with antibrowning agents (4.9 g/kg cysteine, 20 g/kg ascorbic acid and 0.134 g/kg 4-hexyl resorcinol) along with osmo-vacuum dehydration (OVD) (502 g/kg sucrose syrup for 10 min at 570 mmHg vacuum followed by a relaxation of 10 min at atmospheric pressure) and stored at 4±2 °C. The samples were analyzed for physicochemical, sensory and microbiological qualities during storage. Changes were found to become significant ( P⩽0.05) after 4 days of storage. During storage for 24 days, a decrease in pH, TSS (°brix), sugars (g/kg), ascorbic acid (g/kg), total phenolics (g/kg), firmness (N), color ( L * value) and sensory characteristics was observed whereas an increase in microbial counts (log cfu/g), acidity (g/kg) and drip losses (ml/kg) was observed. The combined treatment of litchis with antibrowning agents and osmo-vacuum dehydration treatment were found to be most effective in preventing the changes and the samples were acceptable (sensory score >7.0) upto 24 days, whereas the samples given only OVD treatment lost acceptability due to poor color after 16 days as compared to 8 days for the control samples (dipped in water for 10 min) during refrigerated storage.