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.