Comparison of Nutritional and Sensory Quality of Vegetables Grown on Aquaponics Technology and Conventional Produces
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Date
2019-06
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Addis Ababa University
Abstract
Aquaponics is one of a sustainable and alternative food production sector that integrates
aquaCUlture with hydroponics. It is an emerg.ing part of aquaculture that uses the natural
interaction between bacteria, fish and plants to change waste into clean water. Compared to soilbased
agriculture and aquaculture production methods, aquaponics has many benefits including
re-use of the wastewater from the growing fish, production of two commodities from a single
system and expanded food production by urban residents. For the sustainability of aquaponics,
the nutritional and sensory quality of the produces should be equivalent or better than the
conventional produces. Thus, this study was aimed to compare the nutritional quality and
customer preference of lettuce (Lacnlca sativa L.) and kale (Brassica carinata) grown on
aquaponic system with that of conventionally grown in soil-based system. Proximate
composition of lettuce and kale was determined using standard methods of AOAC and mineral
content was determined by Inductively Coupled Plasma Optical Emision Spectroscopy. Sensory
test was also determined by using discriminatory, preference and rating acceptance test methods.
Accordingly, the aquaponic lettuce from Shewa Robit site had a significant (p<O.05) higher
amount of crude fiber, magnesium, potassiWll, iron; copper, and boron compared to soil-grown
lettuce. Meanwhile the aquaponic lettuce from Addis Ababa University site had significantly
higher amount of crude fat, crude ash, cmde fiber, calcium, magnesium, phosphorus, iron, boron,
copper, and manganese than soil-based lettuce. Aquaponic kale had a significant higher amount
of crude protein, crude fat, cmde ash, crude fiber, zinc, copper, manganese, and macro minerals
than the soil-based kale. However, the aquaponic lettuce and kale at both sites had lower
concentration of vitamin C and ~-carotene than the soil-based lettuce. A higher concentration of
nitrate (78.4811g/g) and (70.7311g/g) was obtained in aquaponic lettuce at Shewa Robit and kale
at AAU site respectively, compared to the soil-based produces. The concentration of chromium,
lead and nickel were lower in the aquaponic lettuce than the soil based havests at AAU site.
Aquaponically grown lettuce and kale at AAU site had a lower sensory preference score
compared with the soil-based produces. The microbial load of the aquaponics system water,
lettuce and kale was within the framework «235 CFU/IOOmL) of EPA for such products. In
conclusion, in this study aquaponically grown lettuce and kale had a better nutritional quality
compared with the soil-based ones. Besides, the heavy metals concentration was within the
acceptable limit of WHOIFAO. Further studies to improve the sensory qualities of the aquaponic
leafy vegetables are strongly recommended from this study.
Keywords: Aquaponics, nutritional quality, customer preference, microbial load, lzmmful metals
Description
Keywords
Aquaponics, nutritional quality, customer preference, microbial load, microbial load