Effect of Nata Formation on Chemical Constituents of Apple Infused Vinegar During Maceration
Date Issued
2008
Date
2008
Author(s)
Chi, Hsuan-Lun
Abstract
Vinegar is a natural acidic food, however, it is generally considered as a physiological alkaline food because it will metabolize into a nalka -line environment in the human body after digestion. The objectives of this study are to investigate the characteristic differences of apple vinegar made from fresh apple slice maceration (ASV)and reconstituted apple juice blending (RAJV); to compare the chemical composition and flavor volatiles of the nata-forming apple slice vinegars (NASV) and ASV; to identify the microflora in NASV and ASV; and to investigate the effect of sucrose concentration on the inhibition of nata-forming bacteria in RAJV.he results of this study showed that the total soluble solids, ammo -nia nitrogen, and acetic acid contents in NASV decreased 0.5oBrix, 0.2 % (g/g), and 2700 mg/kg, respectively, as compared to ASV after 30 days of maceration, however, the formaldehyde nitrogen, malic acid, and gluconic acid content increase 0.7 mg/100g, 320 mg/kg, and 2910 mg/kg, respectively. In the results of flavor analyses showed that, acetic acid decrease 20.5 %, and ammonia compound increase 7 % in NASV, as compared to ASV. ompare the chemical compositions of RAJV and ASV indicate that, ammonia nitrogen, formaldehyde nitrogen, and acetic acid contents increased 0.16 % (g/g), 0.19 mg/100g, and 867 mg/kg, respectively in RAJV; and malic acid and gluconic acid contents decreased 435 mg/kg and 1180 mg/kg, respectively. The aroma volatiles contents of RAJV and ASV are relatively similar. ddition of sucrose to RAJV soluble solids content to above 30oBrix effectively inhibited the growth of nata-forming bacteria. No viable bacteria is found in commercial rice vinegar and washed apples, which indicated the nata-forming bacteria found in NASV and nata-forming reconstituted apple juice blending vinegars (NRAJV) may come from contamination. The nata-forming bacteria in NASV was identified as Gluconacetobacter xylinus.
Subjects
apple
infused vinegar
Gluconacetobacter xylinus
bacterial cellulose
nata
Type
thesis
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