i THERMAL PROCESSING EFFECTS ON TOTAL ... - McGill University

and flavonols, together with trans-resveratrol-3-O-glucoside, as well as higher
concentrations of proanthocyanidins are found in the seed coat, whereas non-flavonoid
phenolics compounds are mainly located in the cotyledons (Dueñas et al., 2002).
Ames et al., (1983) reported that the majority of antioxidants from lentils were
phenolics and polyphenols. In lentil seeds, most phenolics, both in terms of quantity and
variety are located in the seed coat. Therefore, the seed coat of lentil-like legumes, which
represents only a small percentage (8-11% dwb) of their total seed weight could be used
as a replacement for synthetic antioxidants (Ronzio et al., 1998). Lentils have the highest
phenolic, flavonoid and tannin contents (6.56 mg GAE g -1 ; 1.30 and 5.97 catechin
equivalents g -1 , respectively) compared to other common beans and pulses (Xu and
Chang, 2007). An optimum antioxidant activity (95%) was obtained when the radical
scavenging activity of a lentil extract was evaluated by using 1, 1-diphenyl-2-picrylhydrazyl
(DPPH) (Halvorsen and Holte, 2002). The phenolic antioxidant activities of legumes are
related to the compounds‘ structure, for example, for the primary antioxidants flavonoids
(Decker, 1997), their antioxidant activity is associated with the position and degree of
hydroxylation (Rice-Evans et al., 1996). According to Xu and Chang (2007), lentils and
red beans are rich sources of tannins. They found the highest amounts of tannins in lentils,
where they ranged in content from 0.12–8.78 mg catechins equivalents g -1 . According to
Fernandez-Orozco et al., (2003), the content of α- tocopherols in lentils ranges from
3.84–8.69 mg g -1 dwb.
2.7 Conclusion:
Consumer interest and health concerns for natural and ready-to-cook pulse
ingredients have recently come into demand. Though lentil-like legumes are rich in
proteins, antioxidant activity, some of their nutritional components reduced their
usefulness as human food with respect to the recommended intake of certain nutrient
levels. Therefore, the use of traditional processing methods such as boiling and roasting,
along with newer electro-technologies such as microwave heating, were applied to the
processing of lentil flours. These methods‘ affect with regards to improving the
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