EFFECTS OF SHORT-TERM GERMINATION AND AUTOCLAVING ON SELECTED COMPOUNDS IN FABA BEAN AND FABA BEAN APPLICATIONS IN LOW-FAT PORK BOLOGNA

Abstract

The overall goal of this project was to investigate the levels of selected chemical components of faba bean (Vicia faba) seeds produced in North America, and the performance of ingredients derived from faba bean in low-fat pork bologna. This project was divided into two studies. In study I, protein, fat, ash, total starch, and total dietary fibre (TDF) were determined in five faba bean cultivars: Snowdrop, Snowbird, Taboar, Fabelle, and Malik, that were produced in North America from three lots representing biological replicates. The effect of short-term germination and autoclaving on the level of undesired compounds, including phytic acid, vicine/convicine, oligosaccharides, and total phenolics, were also evaluated. Faba bean varieties had 30-33% protein, 3-4% ash, ~1% fat, 35-40% starch, and 25-27% total dietary fibre. Phytic acid in faba bean was 1.6-1.8% with no statistically significant difference between varieties. Seeds of Fabelle variety had the lowest (p<0.05) vicine and convicine content. No significant difference was found among cultivars for the levels of oligosaccharides. The contents of verbascose (37.5-64.0 mg/g) and stachyose (20.4-25.5 mg/g) were higher than raffinose (8.7-8.9 mg/g) content for all faba bean cultivars. Content of total phenolics among faba bean varieties was significantly (p<0.05) different. Snowdrop and Snowbird had the highest content of total phenolics, while Fabelle had the lowest values for total phenolic content. Germination had no significant effect on phytic acid, vicine (except Snowbird), and convicine levels in faba bean seeds. The oligosaccharides showed significant (p<0.05) reduction upon germination: raffinose by 100%, stachyose by 60%, verbascose by 80% at 72-hour of germination. Upon germination, total phenolic content in Snowdrop and Snowbird showed significant reduction but not Taboar, Fabelle, and Malik varieties. Autoclaving did not present a significant (p<0.05) effect on phytic acid, vicine /convicine, and oligosaccharides while the total phenolic content showed a significant reduction (15-23%) after autoclaving, especially for the varieties of Taboar, Snowbird, and Malik. In study II, six binders, including wheat flour, pea starch, cotyledon flour (Malik), cotyledon flour (Fabelle), faba bean starch fraction (commercial), and faba bean protein fraction (commercial), were used in production of low-fat pork bologna with two (1.5 and 3%) incorporation levels. Further their chemical composition and functional properties were investigated, and the physicochemical, textural, and sensory properties of bologna were evaluated. All binders significantly (p < 0.05) increased viscosity of the raw meat batters. The cook loss of all bologna products with binders was low (0.5%, w/w) and no significant difference on purge loss among all binders was observed. Products with 3% wheat flour and faba bean protein fraction had significantly lower expressible moisture values when compared to the control. The colour parameters of cooked bologna surface were in a narrow range of L* (69-70), a* (16-18), or b* value (14-16). The texture profile analysis (TPA) showed binders did not change the hardness, cohesiveness, springiness, and chewiness of bologna compared to the control. Bologna with 3% of wheat flour significantly (p<0.05) increased the torsional true stress at failure compared to the control product without a binder while only a limited effect on shear strain was observed. Sensory evaluation of these products by a 12-member trained panel indicated that that the addition of 3% wheat flour resulted in significantly higher sensory firmness scores than the control. Except the products containing Malik cotyledon flour, addition of other binders at 3% significantly (p<0.05) reduced the perception of juiciness of bologna. Products containing binders at 1.5 or 3% showed no effect on graininess and overall flavour intensity scores except the bologna with 3% of Fabelle cotyledon flour which had significantly (p<0.05) increased intensity of foreign flavour. No significant difference was found in overall acceptability among bologna with any of the binders at either level. Faba bean ingredients showed similar effect on textural and sensory properties of bologna products as compared to reference binder ingredients, showing their potential in low-fat meat products.