Effects of Pitaya Peel Supplementation on Nutritional Quality, Overall Sensory Acceptance, In Vitro Glycemic Index, and Antioxidant Release from Fiber-Enriched Cookies

Abstract

Pitaya peel is a by-product of fruit processing. In this study, the effects of pitaya peel supplementation in the cookie recipe on the nutritional quality, in vitro glycemic index, and antioxidant release from the enriched fiber cookies were investigated. The higher the ratio of pitaya peel powder (PPP) in the recipe, the greater the dietary fiber, betacyanin and phenolic contents, and antioxidant activities of the product. Cookies supplemented with 10–25% PPP were classified as having a low glycemic index, ranging from 51.9 to 45.7 in relation to glucose reference. The release of betacyanins, phenolics, and antioxidant activities from the cookie samples was recorded at the salivary, gastric, intestinal, and colon steps during in vitro sequential digestion, and the gastric digestion showed the highest release of antioxidant content and activity. The increased PPP ratio in the cookie recipe improved the antioxidant activities of the aqueous fractions at the four digestive steps. Statement. This study has a preprint entitled “Effects of the ratio of pitaya peel powder on the product quality, predicted glycemic index, and antioxidant release during in vitro sequential digestion” (DOI: https://doi.org/10.21203/rs.3.rs-2322871/v1). This preprint was posted on the research square website on December 5th, 2022.

Dietary fiber-and antioxidant-enriched cookies prepared by using jackfruit rind powder and ascorbic acid

“…The antioxidant activities of cookies with 40 % JFR powder were 12 times and 15 times higher than those of the control cookies, as quantified by DPPH and FRAP assays using Trolox as the standard, respectively. Similar improvement in dietary fiber and antioxidant contents of the fortified cookies is recently reported when food processing by-products such as pitaya peel [ 40 ] or spent green tea leaves [ 41 ] are added into cookie recipes.…”

Quality of High-Fibre Pasta Supplemented with Watermelon Rind Powder with Different Particle Sizes

“…According to the Codex Alimentarius (2013) Guidelines for Use of Nutrition and Health Claims ( 44 ), all pasta samples containing watermelon rind in this study were classified as high-fibre foods since their TDF content on dry mass basis was above 6 g/100 g. In addition, the IDF/SDF ratio of the high-fibre pasta samples progressively decreased when the sieve aperture size for watermelon rind powder was reduced from 400 to 149 µm. It can be concluded that all pasta samples supplemented with watermelon rind powder had an IDF/SDF ratio suitable for human consumption, since the ratio was almost within the range of [1-3] recommended by the American Dietetic Association ( 3 , 29 ). A high IDF/SDF ratio is usually observed in pasta fortified with cereal bran such as wheat bran (7.0) ( 3 ) or rice bran (9.0) ( 31 ).…”

“…It can be noted that the larger the particle size of watermelon rind powder, the more the antioxidant contents and activities released from the fortified pasta in the oral, gastric and intestinal phases of the in vitro digestion. It has been reported that many phenolic compounds in watermelon rind bind to dietary fibre in the plant cell wall ( 49 ) and could be released during human digestion ( 29 ). The bioaccessibility of total phenols and predicted glycaemic index of all pasta samples are shown in Fig 2 .…”

“…The in vitro glycaemic index for all pasta samples was determined following the procedure reported by Mai et al ( 29 ). White bread was used as a reference sample (its glycaemic index was 71).…”

“…After every 15 min of incubation (from 0 to 180 min), a portion of the aliquot was collected, enzymatically inactivated, centrifuged (model 3K30; Sigma Zentrifugen Ltd.) and the obtained supernatant was used to measure reducing sugars spectrophotometrically, with DNS reagent and glucose as a standard. Predicted glyceamic index was calculated using the formula described by Mai et al ( 29 ).…”