UTILIZATION OF PULSES IN LOW-GLYCEMIC EXTRUDED PET FOODS: EFFECTS OF PULSE VARIETY, PROCESSING CONDITION, AND ROSEMARY EXTRACT
| dc.contributor.advisor | Ai, Yongfeng | |
| dc.contributor.committeeMember | Nickerson, Michael | |
| dc.contributor.committeeMember | Weber, Lynn P. | |
| dc.contributor.committeeMember | Warkentin, Thomas D. | |
| dc.contributor.committeeMember | Low, Nicholas | |
| dc.contributor.committeeMember | Tulbek, Mehmet C. | |
| dc.contributor.committeeMember | Joye, Iris | |
| dc.creator | Ren, Yikai | |
| dc.creator.orcid | 0000-0003-4653-7690 | |
| dc.date.accessioned | 2023-04-13T19:07:04Z | |
| dc.date.available | 2023-04-13T19:07:04Z | |
| dc.date.copyright | 2023 | |
| dc.date.created | 2023-03 | |
| dc.date.issued | 2023-04-13 | |
| dc.date.submitted | March 2023 | |
| dc.date.updated | 2023-04-13T19:07:05Z | |
| dc.description.abstract | This dissertation research aimed to investigate the effects of pulse varieties, extrusion conditions, and addition of rosemary extract (RE) on the physicochemical properties and starch digestibility of extruded dry pet foods. In the first study, wrinkled (WPF) and round pea flours (RPF) of two different particle sizes were prepared and analyzed. Compared with RPF, WPF had lower starch contents (25.4-29.4% versus 46.0-51.2%, dry basis, db), higher amylose contents of starch (69.9-73.6% versus 34.7-39.0%, dry starch basis, dsb), and higher protein (25.4-29.6% versus 21.3-24.7%, db) and dietary fiber (22.4-28.2% versus 14.5-17.9%, db) contents. WPF showed higher conclusion gelatinization temperatures but substantially lower pasting viscosities at heating temperatures of 95-140°C. After cooking, WPF exhibited significantly lower in vitro starch digestibility than RPF. Particle size and growing location also impacted certain physicochemical properties of both WPF and RPF. This study indicated that high-amylose WPF could be a desirable ingredient for the development of low-glycemic pet foods. In the second study, flours of rice (control), round pea, lentil, faba bean, and wrinkled pea were selected to produce extruded dry pet foods under ‘mild’ and ‘extreme’ conditions: i.e., 30% versus 20% in feed moisture, 40, 60, 80, 100 and 120°C versus 40, 60, 90, 120 and 140°C in barrel temperatures, and 200 versus 300 rpm in screw speed, respectively. Under both conditions, wrinkled pea pet foods from both varieties (CDC 4140-4 and Amigold) showed lower damaged/gelatinized starch contents (53.5-69.6% versus 76.0-92.9%, dsb) and less molecular breakdown than the other samples. For all formulations, the ‘extreme’ condition gelatinized and degraded starch to a greater extent than the ‘mild’ condition, which was consistent with the calculated specific mechanical energy during extrusion. Wrinkled pea pet foods demonstrated notably lower starch digestibility in both in vitro (81.0-87.6%, dsb, after 180-min hydrolysis) and in vivo (87.7-89.7%) studies than other formulations (94.5-99.9%, dsb and 97.7-98.3%, respectively). This study demonstrated that both pulse varieties and extrusion parameters could effectively impact physicochemical properties and starch digestibility of pet foods. In the third study, pet foods were extruded using rice, round pea, and wrinkled pea flours with RE incorporated at different levels (0%, 0.1%, 1.0%, and 3.0%, db). Addition of RE notably increased total phenolic contents (from 1.40-1.56 mg GAE/g to 1.84-9.66 mg GAE/g) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability (from 0.3-0.9% to 5.4-85.8%) of the pet foods. At 1.0% and 3.0% levels, RE significantly decreased the starch digestibility of pet foods in vitro (from 94.5-98.9% to 87.1-95.9%, dsb, after 180-min hydrolysis). Although 0.1% RE did not exhibit prominent impacts on the overall starch digestibility both in vitro and in vivo, it consistently postponed the peak times of postprandial blood glucose responses to the three different diets in beagles from 60.0-91.9 min to 90.0-150.0 min. This study suggested that RE could effectively enhance the antioxidant properties (as measured by DPPH radical scavenging assay) and slow down the starch digestion rates of the extruded pet foods. This dissertation research has provided valuable information for the industry to develop low-glycemic pet foods with enhanced functional and nutritional characteristics. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | https://hdl.handle.net/10388/14564 | |
| dc.language.iso | en | |
| dc.subject | Pet food | |
| dc.subject | Pulses | |
| dc.subject | Starch digestibility | |
| dc.subject | Extrusion | |
| dc.subject | Rosemary extract | |
| dc.subject | Wrinkled pea. | |
| dc.title | UTILIZATION OF PULSES IN LOW-GLYCEMIC EXTRUDED PET FOODS: EFFECTS OF PULSE VARIETY, PROCESSING CONDITION, AND ROSEMARY EXTRACT | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Food and Bioproduct Sciences | |
| thesis.degree.discipline | Food Science | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy (Ph.D.) |