Objective: To evaluate the stability and bioavailability of polyphenols in pili (Canarium ovatum Engl.) pomace during simulated in vitro digestion.
Methods: Freeze-dried pili pomace was subjected to in vitro digestion simulating con-ditions in the stomach, small intestine and colon. Total polyphenols, anthocyanins, flavonoids and condensed tannins, and its antioxidant activity– 1,1-diphenyl-2-picrylhydrazyl, 2,20-azinobis-3-ethylbenzothiozoline-6-sulfonic acid, and ferric reducing antioxidant power were measured using standard spectrophotometric methods.
Results: In vitro digestion of pili pomace resulted in reduction of phenolic compounds. Condensed tannins and anthocyanins were released in the gastric and intestinal stages, while total polyphenols and flavonoids after fermentation simulating colonic conditions. Antioxidant values of the bioavailable fractions showed that more than 90% of activity was lost during simulated digestion.
Conclusions: Findings indicate that pili pomace is a promising functional ingredient for food and dietary supplements which can furnish potentially bioavailable phenolic anti-oxidants to the body.

Objective To evaluate the stability and bioavailability of polyphenols in pili (Canarium ovatum Engl.) pomace during simulated in vitro digestion. Methods Freeze-dried pili pomace was subjected to in vitro digestion simulating conditions in the stomach, small intestine and colon. Total polyphenols, anthocyanins, flavonoids and condensed tannins, and its antioxidant activity – 1,1-diphenyl-2-picrylhydrazyl, 2,2′-azinobis-3-ethylbenzothiozoline-6-sulfonic acid, and ferric reducing antioxidant power were measured using standard spectrophotometric methods. Results In vitro digestion of pili pomace resulted in reduction of phenolic compounds. Condensed tannins and anthocyanins were released in the gastric and intestinal stages, while total polyphenols and flavonoids after fermentation simulating colonic conditions. Antioxidant values of the bioavailable fractions showed that more than 90% of activity was lost during simulated digestion. Conclusions Findings indicate that pili pomace is a promising functional ingredient for food and dietary supplements which can furnish potentially bioavailable phenolic antioxidants to the body.

BACKGROUND

Polyphenol intake is associated with reduced cardiometabolic risk factors such as dyslipidemia, hyperglycemia, and obesity. Pigmented rice varieties such as red, purple, and black rice contain polyphenols; however, are not commonly consumed. Apart from price and sensory properties, awareness of its availability, perception of health benefits, and intent to purchase may influence consumer preference and consumption.

This study aimed to develop and validate a short questionnaire designed to determine awareness of the availability, perception of health benefits, and intent to purchase pigmented rice.

The study included three phases: (1) tool development, (2) expert validation, and (3) reliability testing. Questions were initially evaluated for clarity and relevance by two Nutritionist-Dietitians and then by seven lay individuals through a focus group discussion. Following the revision, seven food and nutrition experts evaluated the face and content validity of the questionnaire. Validity was assessed via computation of Item and scale content validity indices and kappa statistics. The validated tool was then tested for internal consistency and parallel form reliability of English and Filipino versions among lay individuals (n=31) and then evaluated for reliability based on Cronbach’s alpha and Intraclass correlation coefficients.

The questionnaire was found to have an acceptable face (I-CVI: 1.00; S-CVI/UA: 1.00; K=1.00) and content validity (I-CVI: 0.86-1.00; S-CVI/UA: 0.96-1.00; K= 0.85-1.00) and reliability (α=0.96-1.00).

The developed questionnaire is a valid and reliable tool for assessing awareness of the availability, perception of health benefits, and intent to purchase pigmented rice.