Probiotics and prebiotic are becoming increasingly important to consumers to alleviate issues surrounding gut health, despite the lack of definitive efficacy studies to support health claims. The addition of both probiotics and prebiotics to foods is challenging due to the harsh environmental conditions within the food itself and during transit through the gastrointestinal (GI) tract. To circumvent these challenges encapsulation technology is being explored to protect sensitive ingredients and to control their release within the lower intestines thereby maximizing the health benefiting effects. The overall goal of this research was to design a protein delivery capsule using phase separated pea protein isolate (PPI)-alginate (AL) mixtures for the entrapment of the synbiot which includes the probiotics, Bifidobacterium adolescentis, and the prebiotic, fructooligosaccharides (FOS), such that the capsule design provides highly effective protection and release within the GI tract. Research was carried out in three studies.<p> In study 1, PPIn (native isolate) and AL interactions were studied in dilute aqueous solutions as a function of pH and biopolymer mixing ratio. Turbidimetric analysis and electrophoretic mobility during an acid titration was used to determine conditions where phase separation occurred. Critical structure forming events associated with the formation of soluble and insoluble complexes in a 1:1 PPIn-AL mixture were found to occur at pH 5.00 and 2.98, respectively, with optimal interactions occurring at pH 2.10. As the PPIn-AL ratio increased, critical pH values shifted towards higher pH until a mixing ratio between 4:1 and 8:1was reached, above which structure formation became independent of the ratios through to ratios of 20:1. Electrophoretic mobility measurements showed a similar trend, where the isoelectric point (pI) shifted from pH 4.00 (homogeneous PPIn) to pH 1.55 (1:1 PPIn-AL). As the ratio increased towards 8:1 PPIn-AL, net neutrality values shifted to higher pHs (~3.80) before becoming constant at higher ratios. Maximum coacervate formation occurred at a mixing ratio of 4:1. Based on these findings, capsule design by segregative phase separation was only used in future studies, due to the acidic nature associated with associative phase separation.<p> In study 2, capsule formation using a native and commercial PPI was studied, and showed no difference between the two formulations during challenge experiments in simulated gastric juice (SGJ). As a result study 3 focused on optimization and characterization of capsules prepared using the commercial PPI. Capsule designs were investigated as a function of protein concentration, prebiotic level, and extrusion conditions (20 vs. 27 G needle) in order to determine protective ability for B. adolescentis within SGJ. Capsule designs were also measured in terms of protein and prebiotic retention during the encapsulation process, geometric mean diameter and size distribution, swelling behaviour and release characteristics within simulated intestinal fluids (SIF). All capsules provided adequate protection over the 2 h duration within SGJ. Capsule breakdown and release was similar for all designs within SIF, with a release mechanism believed to be tied to enzymatic degradation of the PPI material within the wall matrix and/or the amount of excessive Na+ present in the SIF. Capsule size was found to be dependent only on the needle gauge used in the extrusion process. Swelling behaviour of the capsules with SGJ was also found to be dependent only on the protein concentration, where capsules shrank once immersed in SGJ.<p> A 2.0% PPI-0.5% AL capsule without FOS and extruded through a 20 G needle represents the best and most cost effective design for entrapping, protecting and delivering probiotic bacteria. Future work to establish the role FOS could play post-release as the entrapping probiotics colonize the GI tract, and the protective effect of the capsules wall on FOS structure during transit is recommended.

Visual quality is one of the major factors that determine the market value of field pea (Pisum sativum L.). Breeding for improved visual quality of pea seeds is currently a challenging task, because of the complexity and lack of sound genetic knowledge of the traits. The objectives of this research were to characterize the genetic basis and identify the genomic regions associated with four key visual quality traits (cotyledon bleaching in green pea, greenness in yellow pea, and seed shape and seed dimpling in both green and yellow types) in field pea. Biochemical and gene expression profiling to understand the molecular basis of post-harvest cotyledon bleaching in green pea was also addressed. Two F5:6 recombinant inbred line (RIL) populations (90 lines from Orb X CDC Striker cross, and 120 lines from Alfetta X CDC Bronco cross) were developed and evaluated for visual quality traits in two locations in Saskatchewan, Canada in 2006 and 2007. The four quality traits evaluated all displayed a continuous range of expression with moderate to high heritability. Two genetic linkage maps utilizing 224 markers (29 simple sequence repeat (SSR) (from Agrogene) and 195 amplified fragment length polymorphism (AFLP)) and 223 markers (27 SSR and 196 AFLP ) were constructed for the Orb X CDC Striker population and the Alfetta X CDC Bronco population, respectively. Multiple quantitative traits (QTL) mapping detected major QTLs on linkage group (LG) IV and LG V, as well as location- and year-specific QTLs on LG II and LG III associated with green cotyledon bleaching resistance. Nine QTLs controlling yellow seed lightness, three for yellow seed greenness, 15 for seed shape and nine for seed dimpling were detected. Among them, 5 QTLs located on LG II, LG IV and LG VII were consistent in at least two environments. The QTLs and their associated markers will be useful tools to assist pea breeding programs attempting to pyramid positive alleles for the traits. The bleaching resistant cultivar CDC Striker had a slower rate of chlorophyll degradation in cotyledons and a higher carotenoid to chlorophyll ratio in seed coats than the bleaching susceptible cultivar Orb when seed samples were exposed to high intensity light. An oligo-nucleotide microarray (Ps6kOLI1) was utilized to investigate the gene expression profiles of CDC Striker and Orb seed coats at different developmental stages. It clearly indicated that the expression of genes involved in the production and accumulation of secondary metabolites was significantly different between these cultivars. The results of both biochemical and gene expression studies suggested the bleaching resistance in CDC Striker was not due to the accumulation of chlorophyll pigments in the cotyledons, but rather due to the ability of seed coats to protect them from photooxidation. Accumulation of specific carotenoids which could bind with the reaction center protein complex more effectively and accumulation of phenolic secondary metabolites which could enhance the antioxidant properties and structural integrity of the seed coats may lead to the bleaching resistant phenotype. Therefore, breeding green pea cultivars with higher seed coat antioxidant properties would improve both visual and nutritional quality. This research has provided several insights into molecular approaches to improve field pea visual quality for food markets.

The main objective of this study was the application of solar energy for drying of parboiled wheat, corn and pea. Drying experiments were performed under open sun and also in the solar-spouted bed drier in which air heated by solar energy was used. The effects of these drying methods on drying rate and quality parameters were investigated for drying of parboiled wheat, corn and pea. The quality parameters evaluated were color, shrinkage, bulk density, apparent density, bulk and internal porosity, microstructure, pore size distribution, sphericity and rehydration ratio. For peas, ascorbic acid content was also measured. In solar-spouted bed drying, drying rates and effective diffusivity values for all samples were determined to be higher and therefore drying time was significantly lower as compared to open sun drying. Effective diffusivities were in the range of 0.30x10-10 m2/s - 0.65x10-10 m2/s for open sun and 1.35x10-10 m2/s - 3.65x10-10 m2/s for solar-spouted bed drying of different samples. In general, better quality parameters for solar-spouted bed dried samples were observed such as less shrinkage, higher rehydration capacities, more homogenous pore size distribution and higher ascorbic acid retention.

Open Access Article

Field pea (Pisum sativum L.) is an important grain legume in western Canada. Growers can, however, be reluctant to include pulse crops such as field pea in their rotation because they are poor competitors with weeds. This thesis research was conducted to determine whether competitive differences exist among semi-leafless field pea cultivars and to determine the mechanism(s) driving competitive differences. Cultivars included in the studies were chosen on the basis of varying seed size and vine length, which are traits known to confer competitive ability. Differences in competitive ability were identified among cultivars as yield loss ranged from 9% to 31% and 14% to 31% for model weed seed return. However, cultivars were inconsistent in their competitive ranking as cultivars typically performed well for one metric, but not both. None of the traits measured in this study correlated with competitive ability. The greenhouse research was unable to identify the mechanism responsible for these competitive differences. Focal pea plants generally responded to the presence of below-ground neighbours by allocating more resources to shoot production. Therefore, semi-leafless field pea cultivars exhibit differences in below-ground responses to neighbours and it may be useful to include this as part of the selection criteria in breeding programs.

Tyrimų tikslas – ištirti diferencijuotą ir kompleksinį aplinkos veiksnių poveikį skirtingų genotipų sėjamojo žirnio (Pisum sativum L.) fiziologinei reakcijai bei nustatyti šių veiksnių tarpusavio sąveikos įtaką fiziologiniams rodikliams. Tyrimų uždaviniai: Nustatyti skirtingos substrato drėgmės ir UV-B spinduliuotės diferencijuotą ir kompleksinį poveikį įvairių genotipų sėjamajam žirniui: 1.Esant dabartiniams klimato veiksnių parametrams. 2.Padidėjusios anglies dioksido koncentracijos sąlygomis. 3.Pakilusios temperatūros sąlygomis. 4.Prognozuojamų klimato veiksnių parametrų sąlygomis (padidėjus CO2 koncentracijai ir temperatūrai). / The aim of research – to investigate the differential and complex effect of environmental factors on the physiological responses of different genotypes of sowing pea (Pisum sativum L.) and to evaluate the impact of factor interaction among factors on physiological indices. The tasks of research: To identify the differentiated and integrated effect of different substrate moisture and UV-B radiation on different genotypes of sowing pea: 1.Under the current parameters of climatic factors; 2.Under the increased CO2 concentrations; 3.Under increased temperature; 4.Under predicted climatic factors conditions (increased CO2 concentration and temperature).

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Gelation properties of a salt extracted pea (Pisum sativum) protein isolate (PPIs) were evaluated with a goal of using this isolate as a meat extender. Microbial transglutaminase (MTG) was used to improve gelation of PPIs, muscle protein isolate (MPI) from chicken breast and the two combined. Gelation properties were evaluated using small amplitude oscillatory rheology and texture analysis. SDS-PAGE and differential scanning calorimetry were used to examine protein structure. Minimum gelation concentration for PPIs was 5%, lower than the 14% obtained for a commercial pea protein isolate (PPIc), possibly because the PPIc undergone denaturation whereas PPIs had not. Storage modulus (G') and loss modulus (G") increased with protein concentration and maximum gel strength for PPIs occurred at pH 4.0 in 0.3M NaCl. Higher or lower pH values affected protein charge and the potential for network formation. Higher salt concentrations resulted in increased denaturation temperatures, to a point where the proteins did not denature at the 95ºC temperature used for gel formation. When both heating and cooling rate were increased, gel strength decreased, though the cooling rate had a greater impact. Chaotropic salts enhanced gel strength, whereas non-chaotropic salts stabilized protein structure and decreased gel formation. Based on effects of guanidine hydrochloride, urea, propylene glycol, β-mercaptoethanol, dithiothreitol and N-ethylmaleimide, hydrophobic and electrostatic interaction and hydrogen bonds were involved in pea protein gel formation but disulfide bond contribution was minimal. Gels formed with MPI at concentrations as low as 0.5% and were strongest at 95ºC, higher than the ~ 65ºC normally used in meat processing. Good gels were formed at pH 6 with 0.6 to 1.2 M NaCl. Addition of MTG increased gel strength for PPIs, MPI, and a combination of the two. SDS-PAGE showed that bands in the 35~100kDa range became fainter with higher MTG levels but no new bands were found to provide direct evidence of interaction between muscle and pea proteins. Improved gel strength for the MPI/PPI mixture (3:1) containing MTG suggested that some crosslinking occurred. Higher heating temperatures and MTG addition led to the formation of MPI/PPI gel and demonstrated the potential for utilization of pea protein in muscle foods.