Amylase activities and patterns were compared in extracts from mature seeds and from different parts of seedlings at various stages of seed germination of various varieties of different legume species. Apart from soyabean, all varieties had low levels of amylase activities in extracts from mature seeds, while the former had a remarkably high level. Amylase activities and the number of bands increased during seed germination and showed time and tissue specifity. The extracts from cotyledons had the highest activities and the largest number of bands as compared to that of the various parts of embryonic axes. Amylase activities and patterns had time specific changes during the various stages of seed development of the 7 varieties of different legume species studied. All the different varieties showed changes in zymogram patterns and decreased amylase activity during seed development, except soyabean where amylase activity remained high at all stages. The different components of amylase were characterised in pea (var. Feltham First). One band of a -amylase activity, restricted to the cotyledons, was present in the middle stages of seed development only, then reappeared at the third day of seed germination. The embryonic axes β -amylase activity decreased as the seed developed, to reach zero level in mature seeds, and reappearred during seed germination. The reverse sequence occurred for the cotyledonary β -amylase. The pea a -amylase was partially purified using ethanol precipitation, glycogen complex and hydroxyapatite column chromatography. The purified protein had three major bands with few faint bands on the SDS polyacrylamide gel. The embryonic axes β -amylase of pea was partially purified using the conventional method, ammonium sulphate precipitation, ion exchange chromatography and gel filtration. The purified protein contained two thick bands and many faint bands on the SDS polyacrylamide gel. The zymogram patterns of phosphorylase, EST, GDH, GOT, LDH, ADH and MDH were investigated during seed development of various varieties of different legume species. The most noticeable changes as the seeds developed were the decrease in activities and number of bands of EST in pea and soyabean, shift in GDH activities between isoenzyme forms in pea (var. English Wonder), increase in GDH activities and number of bands in dwarf French bean and soyabean and increase in activities and number of bands of MDH in pea (var. Feltham First).

New food innovation is largely based on consumer demand, and currently many consumers demand healthy foods with clean label ingredient statements and plant-based origins. Sprouted grain products meet these qualifications and thus are growing in popularity. Sweetened products have been made from oats by adding exogenous amylase enzymes to hydrolyze starch into sugars. The purpose of this study was to create a clean label oat sweetener using endogenous enzymes. First, amylase activity under various sprouting conditions was determined for 4 hulless and 10 in-hull oat varieties. Paul (hulless variety) and Horsepower (in-hull variety) had the highest amylase activity after sprouting 120 h at 16°C. The amylase activity in these two varieties was then further optimized by determining the highest amylase activity occurred by sprouting for 120 hours at 24°C. Second, amylase activity was determined for these two varieties after oven-drying and freeze-drying of sprouted oats, followed by a 4-week ambient storage period. Paul decreased in alpha-amylase activity for both oven-dried and freeze-dried samples, whereas Horsepower remained constant in its amylase activity for oven-dried and freeze-dried samples. Stored samples were also analyzed for susceptibility to lipid oxidation using SPME-GC-MS. All hexanal levels rose during the 4-week storage study except for the oven-dried Paul samples which began high and decreased over time. Third, a slurry of sprouted Horsepower oats, oat flour, and water was incubated at 45, 55, and 65°C to determine the optimal temperature needed to create a sweetened paste for use in oat-based food products. Incubation at 55°C had the highest initial rate of sugar production as measured by normal phase HPLC. Amount of sugar produced increased over time and plateaued at 6 h.

In this study sprouting two different wheat cultivars under various environmental conditions revealed that varietal variation is the most important factor affecting α-amylase quantity as well as quality to modify flour functionality significantly, followed by pre-soaking duration and temperature. Sprouted wheat flour post five days germination was utilized at different rates to prepare 100 g composite breads. There was an improvement in baking quality and shelf life of breads containing 1% and 5% sprouted flour resulting in a significantly increased loaf volume, better texture, and less retrogradation during 7 days post baking than the control. This study presents opportunities for industry to fortify baked products with sprouted wheat flour to yield functional whole grain products that are nutrient dense and naturally shelf-stable. / MITACS

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Digestion of starch in humans starts in the mouth and progresses to the small intestine. Structures from salivary and pancreatic amylases hydrolysis can impact subsequent steps of digestion at the mucosa of the small intestine. However, structures of the starch digestion products along the gut from the mouth to the small intestines – products that impact glucose homeostasis are not well understood. This thesis focuses on the luminal step of starch digestion, i.e. impact of salivary and pancreatic amylase on the structure of hydrolysis products obtained from cooked starches from different botanical sources. Normal corn (NCS), wheat (NWS) and potato (NPS) starches were cooked at 1:0.7 (T0.7) or 1:2 (T2) starch:water ratios. Cooked starches were subjected to salivary amylase at conditions mimicking oral digestion. The composition of the hydrolysates was characterised by gel-permeation chromatography. Extent of hydrolysis was lower at T0.7 compared to T2, but the amount of carbohydrates in different fractions and the molecular weight profiles within each treatment were not different between starches from different botanical sources. However, debranching of the hydrolysates revealed structural differences in extent of amylose hydrolysis and amount and profile of lower molecular weight fractions between different starches. Cooked starches were also subjected to salivary and pancreatic amylases hydrolysis. Extent of 20 min hydrolysis was lower at T0.7 compared to T2 for all the starches. Oligosaccharide composition of 120 min hydrolysates differed in amounts of DP 2, 3, 5, 6 and 7 between processing treatments and starches. NCS (T2) was treated with saliva from six participants at equal activity. Salivary amylase activities ranged from 470 x 103 to 118 x 103 U/mL among the participants. While saliva from participant 2 (high amylase activity) greatly reduced the high molecular weight fraction, saliva from participant 6 (low amylase activity) more extensively hydrolysed the starch to small molecular weight fractions of oligosaccharides. These results show that different starch hydrolysates are produced during oral digestion by saliva from different individuals and are also different based on cooking condition or botanical source of starch. Further research is therefore needed to understand how these hydrolysate structures, impact glucose homeostasis.