Effects of onion peel wastes on nutritional and organoleptic quality assessment of smoked <i>Clarias gariepinus</i>

Abstract

The wastes from onion usually litter sales outlets in various markets across the country. Onion (Allium cepa) peel wastes (OPW) was  assessed for its chemical content, nutritional and organoleptic quality on smoked catfish (Clarias gariepinus) stored for a duration of 8  weeks at room temperature. The OPW at concentrations of 0g, 2.5g and 5g (T0, T1 and T2 respectively) were sprinkled on the fish samples  before and after smoking. Samples of OPW and fish were analyzed chemically for proximate composition, and determination of  organoleptic quality according to standard method by panel of 20 on a 9-point hedonic scale. Nitrogen free extract (43.26%) constituted  the highest analyte of the OPW. This was followed by ash (32.95%); crude fibre (11.45%); moisture content (6.69%); crude protein (4.40%)  and ether extract (1.25%). The composition of fish preserved with OPW was significantly different when compared with the initial and  final carcass analysis of the control group. The analysis revealed crude protein in T0 (49.84%), T1 (36.91%), T2 (43.13%); ash in T0 (7.70%),  T1(14.05%), T2 (8.20%) while ether extract T0 (8.65), T1 (5.55%) and T2 (7.76%). In terms of organoleptic assessment, all the mean values  of the fish samples were above 5 which indicated that they were not disliked. The control fish, T0 (0.0g/0.5kg) had superior taste, 7.95%;  appearance, 7.60%; aroma, 7.45%; texture, 7.60% and acceptability, 7.85%. this was followed by T2 (5.0g/0.5kg) with no significant  variation (p < 0.05) among the test samples. Inference from the study showed that OPW at 5g can be used to preserve smoked fish  without change in quality, sensory and organoleptic assessment for 8 weeks.