CHEMICAL PROPERTIES OF VINEGAR PRODUCED FROM SWEET ORANGE PEELS (CITRUS SINENSIS)
Oguntoyinbo, S.I.1, Babajide, J. M.2, Adenekan, M. K.3, Ajayi, J.O.4 and Kareem, S.O.5, Ayelaagbe, I.O.O.6, Atanda, O.O.7, Bodunde, G.8
1, 3, 4Department of Food Technology, Moshood Abiola Polytechnic, Abeokuta, Ogun State, Nigeria
2,,5,6,7,8 Federal University of Agriculture, Abeokuta, Ogun State, Nigeria
E-mail: graceyetty@yahoo.com
ABSTRACT
This study reports the chemical properties of vinegar produced from sweet orange (Citrus sinensis). The peels were digested with α- and β- amylases, amyloglucosidase and fermented with Saccharomyces cerevisae and Acetobacter aceti for 2, 4, 6, 8, 10, 12 and 14 days. Acetic acid, total acidity, pH, total solids, total sugar, ethanol content, ester value, oxidation value and iodine value of the vinegar were determined. After 8 days of fermentation, vinegar produced gave acetic acid (5.00%) and total acidity (15.00%) values which were not significantly different (p>0.05) from those of cider vinegar (R) (5.10% and 15.33% respectively). Vinegar produced at 14 days fermentation gave pH (3.46) and total solid content (8.70%) values of no significant difference (p>0.05) from R (3.56 and 8.87% respectively). At the end of 14 days of fermentation, total sugar content reduced gradually from 2.22 to 0% for all the samples which falls within the range for R (0 – 2.50%). Sweet orange peels fermented for 14 days produced vinegar that contained 0.60 and 0.78% respectively for ethanol and 20.04 and 20.00 ml/100ml respectively for oxidation value with no significant differences (p>0.05) from R (0.63 and 20.00 ml/100ml respectively). At 14 days fermentation, the vinegar produced gave ester (4.13 ml/100ml) and iodine (8.05 g/100g) values which were not significantly different (p>0.05) from R (4.00 ml/100ml and 8.00 g/100g respectively). This study revealed that vinegar could be produced from sweet orange peels asfermentation for 14 days gave the highest yield of 75% v/v. Thus, sweet orange peel vinegar could be of high importance as import substitute for cider vinegar and value addition in the citrus industry which provides an alternative economically viable use of citrus fruit peels that are usually regarded as wastes and of no value.
Key Words: Fermentation, Digestion, Acetic Acid, pH