Semester of Graduation

Spring 2022

Degree

Master of Science (MS)

Department

Nutrition and Food Sciences

Document Type

Thesis

Abstract

Consumption of gluten-free (GF) products remains a fast-growing trend. Quinoa flour (QF) is a good source of protein (14-18%), coconut flour (CF) is rich in fiber (60%), and papaya seed is currently a discarded/waste material but rich in bioactive compounds, dietary fiber, and protein. Therefore, papaya seed can be incorporated into products to enhance health benefits. However, at a higher level of incorporation, it imparts bitterness/off-taste. Therefore, the following studies were conducted: a) To formulate GF chocolate cupcakes (GFCCs) made with QF, CF, and papaya seed flour (PSF), and evaluate their selected physical properties and consumer perception; b) To determine Multi-Attributes-Based Rejection Tolerance Threshold (MA-RTT) and Rejection Range (RR) for papaya seed flour (%PSF) incorporated in chocolate quinoa cupcakes (CQCs).

In the first study, GFCC with 100% QF was acceptable for all sensory attributes (scores of 5.86-7.28). All GFCCs were not significantly different in liking of aroma (6.87-7.14), moistness (6.37-6.44), softness (6.68-7.13), texture (6.05-6.54), flavor (5.81-6.34), and overall-liking (5.86-6.38). Visual-quality and appearance of GFCC with 100% QF were more acceptable than GFCC with QF:CF=50:50 due to darker (lower L*), and less reddish (lower a*) and yellowish (lower b*) color. Most consumers (85%) penalized moistness of GFCCs for ‘not-moist-enough’, resulting in overall-liking mean drops of 0.77-1.55. The high overall-liking score (6.38) of GFCC with QF:CF=75:25 was likely associated with emotions, particularly ‘satisfied’ and ‘pleasant.’ PI after the fiber claim given to consumers significantly increased by 1.3 (for QF:CF=75:25) to 1.9 (for QF:CF=100:0) times compared to those before the claim.

In the second study, a critical value was found at 60 “Yes” acceptability response. Based on this critical value, the rejection rate was 35% to determine MA-RTT35 and RR95 (95% confidence interval). RTT35 for flavor and overall acceptability was at 6.6% and 7.8% PSF, respectively; therefore, MA-RTT35 was established at 6.6-7.8% PSF. RR95 for flavor and overall acceptability was 5.0%-8.9%, and 6.6%-9.7%, respectively.

Overall, this study demonstrated the use of MA-RTT and RR method to establish the maximum level of PSF that can be incorporated in CQCs without being rejected by consumers.

Committee Chair

Prinyawiwatkul, Witoon

DOI

10.31390/gradschool_theses.5494

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