Assessment of antioxidant and functional properties of Jamun (Syzygium cumini L.)
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Date
2014
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Punjab Agricultural University
Abstract
The investigation was carried out to assess the antioxidant and functional properties of jamun,
optimization of the supplementation levels of jamun powder in various food products namely pear juice,
papaya fruit bar, extruded snacks and chapatti and to investigate the shelf life of jamun supplemented
products. The physico-chemical and bioactive analysis showed that jamun powder was a good source of
crude fibre, ash, anthocyanins and total phenolic content. Freeze dried jamun powder retained better
bioactive compounds and had 44.27, 17.53, 13.35 and 5.75 per cent higher ascorbic acid, anthocyanins,
total phenols and antioxidant activity, respectively as compared to hot air dried jamun powder. Optimum
supplementation level of jamun powder in the products was selected on the basis of sensory evaluation
and could be supplemented up to 4, 5, 10 and 3 per cent in pear juice, papaya fruit bar, extruded snacks
and chapattis, respectively. Color analysis revealed lower L*, b* and higher a* values for all the jamun
powder supplemented products as compared to control except papaya fruit bar where a* values decreased.
Blending of jamun powder with pear juice, papaya fruit bar, extruded snacks and chapattis, enhanced
bioactive components and per cent increase in antioxidant activity was 18.13, 56.41, 96.55 and 32.08,
respectively than control samples. Supplemented pear juice showed higher mean values for titratable
acidity (0.33 %), reducing sugars (7.97%, dextrose) and total sugars (10.37%, dextrose) as compared to
control. For supplemented papaya bar slightly lower mean values were recorded for moisture (19.45%),
TSS (76.26˚B), reducing sugars (22.23 %, dextrose) and total sugars (63.35%, dextrose) as compared to
control. Not much variation was observed in total ash, crude fibre and crude protein content of control and
supplemented samples. Decrease in expansion ratio, water absorption index and increase in bulk density,
hardness and water solubility index was observed in supplemented extruded snacks. After
supplementation with jamun powder, ash content increased by 4.31 per cent and fibre content increased by
5.82 per cent in chapattis. Freeze dried jamun powder supplemented chapattis were softer than chapattis
supplemented with hot air dried jamun powder. Negligible effect of drying method and storage period on
total ash, crude fibre and crude protein content of the jamun powder supplemented products was observed
during 6 months of storage. During storage period, all the bioactive compounds and antioxidant activity
decreased significantly (p≤0.05) in control and supplemented samples. Storage studies showed that jamun
powder supplemented products could be stored safely at ambient temperature without significant changes
in sensory attributes. All the jamun powder supplemented products were microbiologically safe during
entire storage period. The products supplemented with freeze dried jamun powder were found nutritionally
superior in terms of bioactive compounds and antioxidant activity as compared to hot air dried jamun
powder supplemented products.
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Keywords
Jamun