Semester of Graduation

Spring 2022


Master of Science (MS)


Nutrition and Food Sciences

Document Type



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



Available for download on Monday, March 19, 2029