Investigating the potential applications of lentil seed components in mechanically separated chicken meat systems
The overall goal of this project was to explore the potential applications of lentil seed components in meat systems. Therefore, their functionality as an antioxidant and a binder were investigated in four studies. In study one, the antioxidant efficacy of water and (70% v/v) ethanol extracts of seed coat from two lentil cultivars (CDC Greenland, a large green and CDC Maxim, a small red variety) were studied in in vitro assays and a mechanically separated chicken (MSC) model meat system. The total phenolics (TPC) extracted in aqueous (70%) ethanol (43.96–50.46 mg gallic acid equivalents (GAE)/g) were higher (p<0.05) than that of water extracts (41.63 –44.30 mg GAE/g). Extracts demonstrated concentration-dependent antioxidant activity irrespective of cultivar or extraction solvent. The addition of seed coat extracts (500 ppm TPC) resulted in significant (p<0.001) inhibition of lipid oxidation in MSC during cooking and storage and there was an 11-fold difference in TBARS values between treated and control samples after seven days of refrigerated storage. The antioxidant capacity of seed coat was comparable to Herbalox, sodium ascorbate, (+)-catechin, and (+/-) - α- tocopherol. In study two, the phenolic composition and antioxidant capacity of water extracts of seven lentil cultivars (CDC Greenland, CDC Greenstar, CDC Maxim, CDC Robin, CDC SB-3, ZT-4 and 6205-ZT) were determined. TPC, flavonoids (TFC) and condensed tannins (CTC) in normal tannin seed coats ranged from 35.88 to 39.72 mg GAE/g, 3.50 to 5.14 mg catechin equivalents (CE)/g and 21.63 to 28.07 mg CE/g, respectively. Condensed tannin was absent in zero tannin cultivars and TPC was around 6-times lower than that of normal tannin cultivars. Kaempferol tetraglycoside, catechin-3-glucoside, and procyanidins were the most abundant phenolic compounds in normal tannin cultivars, whereas kaempferol tetraglycoside was dominant in zero tannin cultivars. Antioxidant activity measured by DPPH, ABTS, and ferrous ion chelation assays showed strong activity (>70%) at concentrations higher than 400 ppm of TPC. Overall, lentil cultivars with seed coat had relatively higher phenolic content and antioxidant activity compared to other cultivars. TPC, TFC and CTC concentrations were highly correlated (r = 0.93 to 0.98) with antioxidant activities showing their positive contribution to antioxidant capacity of seed coat. Both free radical scavenging activity and chelation mechanisms were involved in the overall antioxidant efficacy of seed components. The objective of the third study was to evaluate the applicability of lentil seed components (flour, seed coat and seed coat water extracts) as replacements for synthetic phosphates in non-cured bologna sausage. The combination of infra-red heated (IR) lentil flour and seed coat extracts (300 ppm or 500 ppm of TPC) were able to replace the techno-functional properties of synthetic phosphates with no negative effects on water-holding, texture, and sensory properties and oxidative stability of bologna, while seed coat itself had negative impact on color, flavor and texture attributes. The fourth study investigated the efficacy of infra-red heated lentil flour as a binder in wiener type chicken sausages developed for the Sri Lankan market. The water-holding and texture properties, and the proximate composition of the sausages containing lentil flour, were similar to those of the commercial formulation made with isolated soy protein and corn starch, and the level of lentil flour added (4% to 8%) had minimal effect. Oxidative stability of sausages formulated with lentil flour was similar to the commercial formulation, and samples with lentil flour showed no difference in oxidative stability compared to those added sodium nitrite. The cross-cultural consumer acceptability tests conducted with three consumer panels (Canadian consumers, Sri Lankan consumers living in Canada and Sri Lankan consumers living in Sri Lanka, each consisting of 60 panelists) revealed that the liking for sensory properties and overall acceptability of MSC sausages were similar between the commercial product and those with lentil flour added, demonstrating that lentil flour could be an economical and effective meat replacer product. The functionality of lentil flour as a binder were possibly attributable to its high amounts of starch and protein. In conclusion, this study demonstrated the potential for use of lentil seed components as a potential plant antioxidant and binder in meat products without decline in sensory characteristics and nutritive value. The findings of this study will help in the development of clean label meat products, nutraceutical applications, and breeding strategies for lentil cultivars with health and functional benefits.
lentil, seed coat, mechanically separated chicken, phenolic compounds, lipid oxidation, sensory properties, consumer acceptability
Doctor of Philosophy (Ph.D.)
Food and Bioproduct Sciences