QUALITY PROPERTIES AND SHELF LIFE EVALUATION OF BREAD AND COOKIES INCOOPERATED WITH ORGANIC PRESERVATIVE EXTRACTS (ANTI MICROBIAL AND ANTIOXIDANTS) OBTAINED FROM NATURAL SOURCES
Orishagbemi, C. Ojo; Michael, O. Edith; Opega, J. Ladi & Odiba, A. Adegede
Department of Food, Nutrition and Home Sciences
Kogi State University, PMB, 1008, Anyigba, Nigeria
Email: cornelosag@g.mail.com
ABSTRACT
Organic extracts containing antimicrobial and antioxidant agents from lemon, tumeric, onion peel and ripe cloves were prepared and used to preserve bread and cookies alongside sodium benzoate chemical preservative, then subjected to sensory property, microbiological and shelf life evaluation at the ambient temperature (28+20C). Each extract was applied at four (4) concentration levels (0.04, 0.06, 0.08 and 0.10g/100g flour) and sodium benzoate (0.03g/100g flour) as control for bread, doughnut and biscuit samples (all coded). They were stored under ambient conditions, subjected to interval routine inspection, sensory, microbiological assessment, shelf life evaluation and data analysis using standard methods in all cases. The colour, taste, flavour and texture of bread loaf were most retained for five (5) days with 0.06g lemon extract/100g flour, similar to the control without any significant difference (p>0.05). Other extracts regardless of their concentration (0.04-010g) were found to retain these sensory attributes for lesser days before onset of mould growth. Also, the sensory attributes (colour, taste and flavour) of doughnut samples were not affected up to 8 days with 0.06g onion peel extract and 0.10g lemon extract /100g flour, while the control sample did not keep more than 5 days in storage. Tumeric and clove extracts, regardless of the concentration (0.04-0.10g) did not preserve doughnut beyond 3 and 6 days respectively. Apparently, extracts of lemon, onion peel and tumeric (0.04-0.010g concentration levels) and control were found to retain the colour, taste and flavour of biscuit for up to 5weeks under ambient storage temperature (28+0C), while clove extract preserved samples had poor colour, taste and flavour ratings regardless of the storage duration. The total plate count (TPC) of bread samples stored up to 5 days with lemon extract ranged from 2.9-4.1×101 cfu/g samples; doughnut with lemon and onion peel extracts kept for 8 days had a range of 5.3 -5.7×10l and biscuit stored for 5 weeks had range, 1.5-3.0 x101 cfu/g sample. However, moulds and coliform were not detected. Although, samples with other extracts with corresponding concentrations that kept for few days as applicable had moulds (1.9-3.6×101 MPN/g sample) which rendered them unsafe for consumption and storage discontinued. Both lemon juice and onion peel extracts are found to be suitable organic antimicrobial /antioxidant agents suitable to replace chemical preservative for bread and cookies (doughnut and biscuit).
Keywords: Organic Preservatives, Fruit/vegetable extracts, Cookies/bread preservation, Antimicrobial agent, Antioxidant.
