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Physicochemical Properties and Antioxidant Activities of T oona Sinensis Roem Leaves as Affected by Drying Methods
Author(s) -
Huang GueyLin,
Wang BeJen,
Weng YihMing
Publication year - 2014
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.2012.00784.x
Subject(s) - chemistry , tbars , dpph , gallic acid , food science , antioxidant , butylated hydroxyanisole , swietenia macrophylla , botany , lipid peroxidation , organic chemistry , biology
Toona sinensis R oem (also known as C hinese toon) is widely distributed in S outheast A sia. The effects of different drying methods (including freeze drying, 65C hot air drying and solar drying) on the antioxidant activities of the toon leaves were investigated. Water and methanol extracts of leaves dried with all three methods exerted up to 94% 1,1‐diphenyl‐2‐picrylhydrazyl ( DPPH ) free radical scavenging activity and showed better reducing powder than butylated hydroxyanisole and α‐tocopherol at the level of 0.8 mg/mL. While methyl gallate was only detected in methanol extracts (99–395 μg/g), the highest amount of gallic acid was found in water extracts (3.21–4.58 mg/g) for its higher polarity. The addition of dried toon leaves reduced the lipid oxidation as represented by thiobarbituric acid reactive substances ( TBARS ) content in toon barbecue sauce; the TBARS values after 4 months of storage for freeze‐dried, hot air‐dried, solar‐dried and control samples were 1.13 ± 0.16, 1.42 ± 0.06, 1.58 ± 0.09 and 2.14 ± 0.09 ppm, respectively. Practical Applications With T oona sinensis R oem ( C hinese toon), although many beneficial properties of toon leaves can be found in the scientific literature, the academic results can hardly be used for the manufacture of commercial products. Toon barbecue sauce, containing solar‐dried toon leaf powder prepared by primitive solar drying in the countryside, is an important vegetarian food product in T aiwan. There is no known research that has been conducted to investigate the effects of solar drying on the quality of the toon leaves and on the antioxidant properties of the sauce. The present research compared the quality of solar‐, hot air‐ and freeze‐dried toon leaves and the resulting toon barbecue sauce. The results can serve as guidelines for the toon barbecue sauce manufacturers to make products with better functional properties.