Recipient Organization
UNIV OF IDAHO
875 PERIMETER DRIVE
MOSCOW,ID 83844-9803
Performing Department
Animal, Veterinary and Food Sciences
Non Technical Summary
Pulse crops have been a valuable component of human and animal diets throughout history. Despite the nutritional potential of pulse crops for food and feed, their utilization is relatively limited. In recent times, there has been a rising demand from consumers for high protein foods and protein isolates. As a result, global pea protein markets are expected to increase with rising health consciousness and growing demand for plant-based food supplements (Grand View Research, 2016). Along with the current trends, there is a looming food deficit on the near horizon. By 2050 the global food demand will need to increase by 70% to feed the growing world population (Ranganathan et al. 2016). To accomplish this, roughly 33% of dietary protein will need to come from alternative sources like protein isolates from pulse crops, oil seeds, cereals, and others (Stice and Olen, 2014). Therefore, the long-term goal of the proposed research is to decrease global food shortages by enhancing the ability to incorporate pulse proteins into the human diet. The immediate objective of this proposal is to increase the functionality of pulse products (flours, starch, and protein isolates) through optimization of processing and biochemical modifications while maintaining or improving nutritional quality. The central hypothesis of this project is that pulse product functionality is dependent on the synergistic effects of the multiple processing steps as well as the biochemistry of the starting material. When complete, this project not only address the objectives listed below, it will deliver a means to add value to pulses, an important group of grain commodities for Idaho and the Inland Northwest. It will accomplish this by providing information on how to better select raw materials and providing new technologies for value-added processing. ?
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
The premise of this research is based on the fact that the biochemistry of pulse crops as it relates to functionality is not well understood. Without this knowledge it is difficult if not impossible to optimize processing condition to provide consumers with consistent product. Here, the greatest hurdle that has prevented successful incorporation of pulse products into foods is large variability inherent to the raw commodity.This proposal utilizes a robust treatment plan to identify these biochemical features while simultaneously assessing how processing affects them. In doing so, this project will address the following objectives:1. Determine the biochemical composition of starting materials2. Optimize extraction protocols for maximum protein solubility3. Determine the effects of glucose addition and deamidation on the functional properties of pulse protein isolates4. Determine the effects of ultra-sonication and chemical disulfide bond cleavage on pulse protein isolate functionality5. Determine the nutritional quality of the experimental treatments through in-vitro digestibility studies6. Developing innovative processes to facilitate inclusion of pulse flours into bread and other bakery applications
Project Methods
Objective 1: Determine baseline values for comparison with treatments in other objectives. Proximate composition, amino acid content, digestibility, molecular weight distributions, reverse phase liquid chromatography (RP-HPLC, FTIR, isoelectric point analysis, surface hydrophobicity and functionality testing will be completed. Molecular weight distributions will be determined by size exclusion liquid chromatography (SE-HPLC) and microfluidic SDS-PAGE analysis. FTIR analysis will focus on the amide I region of the spectra. Deconvolution and quantification of β-sheet (1620-1638), random (1638-1650), α-helices (1650-1658), turn (1658-1679), and antiparallel β-sheet structures will be completed. The solubility, foaming properties, emulsion properties, and gelling properties will be assessed for functional analysis.Objective 2: Optimize extraction protocols for maximum protein solubility.Proteins will be extracted from pulse flour and from pulses steeped in water for 12 hours and ground. Extractions will be completed at native pH and pH 8.0. After centrifugation, proteins will be precipitated with HCl addition. Optimization of terminal precipitation pH (3.5-4.5) will be assessed based on solubility of dried isolates. After precipitation and centrifugation, the precipitant will be washed once with DI water and centrifuged again. The remaining pellet will then be re-suspended and brought to pH 7 with NaOH. The duration of each step will be standardized. After re-suspension, proteins will be either freeze dried or spray dried. For freeze drying, samples will be immediately frozen, allowed to rest for 30 min prior to freezing, and subjected to a mild heat treatment prior to freezing. For spray drying, samples will be rested for 30 min prior to drying, frozen and thawed prior to pray drying, and dried at the different temperatures. Treatments will be subjected to analyses described in objective 1.Objective 3: Determine the effects of glucose addition and deamidation on the functional properties of pulse protein isolates. Objective 3 will be completed using the best and worst treatment from objective 2. Because the bulk of pulse proteins have a strong affinity for glucose and preliminary results demonstrate an increase in solubility with glucose, addition of 0 - 15mM glucose in 3.0mM increments will be added to the extraction water. Deamidation will also be studied. While pulse glycoproteins have a strong affinity for glucose, they will also bind other carbohydrates and substrates decreasing solubility. The binding site of vicilin requires asparagine to function. Conversion of arginine to aspartic acid and/or isoaspartic acid by deamidation should prevent the binding of undesirable substrates, increasing protein solubility. Deamidation will be completed with Alcalase at pH 10 (Kato et al., 1987). Treatment will be subjected to analyses described in objective 1.Objective 4: Determine the effects of ultra-sonication and chemical disulfide bond cleavage on pulse protein isolate functionality. From objective 2, the best and worst treatment protocol for each pulse will be subjected to disulfide bond cleavage through ultra-sonication and cysteine addition. The cleavage of disulfide bonds will decrease the average Mw and decrease reduce the pulse protein's ability to bind other substrates, both of which will result in increased solubility. Ultra-sonication will be completed during extraction at 10 watts (Smith et al., 2010). Cysteine, with its free S-H groups is quite effective a cleaving disulfide bonds. Cysteine will be added at a rate of 0.0-1.0% in 0.25% incrementsObjective 5: Determine the nutritional quality of the experimental treatments through in-vitro studies. Over the duration of the study, treatments will be collected and stored at -80°C. Upon completion of objectives 1-4, in vitro digestabilities will be completed based on methods described by Martín-Cabrejas et al., (2009).Objective 6: Developing innovative processes to facilitate inclusion of pulse flours into bread and other bakery applications. Dehulled dry split peas will be milled on Miag pilot roller mill. This mill produces 11 individual streams using typical corrugated and smooth rolls that employ crushing and shearing forces, with automatic pneumatic conveying and sifting operations. Each stream will be evaluated for protein and fiber composition, damaged starch, particle size distribution, water holding capacity, starch pasting and rheology, and mechanical "dough" mixing characteristics. Selected and composited flour streams will be used to blend with a commercial bread flour and a commercial pancake mix. Effects of pea flour on gluten strength and extensibility, dough mixing, water absorption, proofing/fermentation, and bread loaf volume and crumb will be evaluated. Effects of pancake batter viscosity, pancake diameter and height, surface color and texture (Texture Profile Analysis by TAX-T2i) will be evaluated. All measurements will be analyzed based on pea flour inclusion rates of 1, 2, 5, 10 and 20% by weight (flour basis). Sensory analysis for pancakes and breads will be carried out as described Bize et al. (2017).