Novel value‐added uses for sweet potato juice and flour in polyphenol‐ and protein‐enriched functional food ingredients

Abstract

Blackcurrant, blueberry, and muscadine grape juices were efficiently sorbed, concentrated, and stabilized into dry granular ingredient matrices which combined anti-inflammatory and antioxidant fruit polyphenols with sweet potato functional constituents (carotenoids, vitamins, polyphenols, fibers). Total phenolics were highest in blackcurrant-orange sweet potato ingredient matrices (34.03 mg/g), and lowest in muscadine grape-yellow sweet potato matrices (10.56 mg/g). Similarly, anthocyanins were most concentrated in blackcurrant-fortified orange and yellow sweet potato matrices (5.40 and 6.54 mg/g, respectively). Alternatively, other protein-rich edible matrices (defatted soy flour, light roasted peanut flour, and rice protein concentrate) efficiently captured polyphenols (6.09–9.46 mg/g) and anthocyanins (0.77–1.27 mg/g) from purple-fleshed sweet potato juice, with comparable efficiency. Antioxidant activity correlated well with total phenolic content. All formulated ingredient matrices stabilized and preserved polyphenols for up to 24 weeks, even when stored at 37°C. Complexation with juice-derived polyphenols did not significantly alter protein or carbohydrate profiles of the matrices. Sensory evaluation of the ingredient matrices suggested potential uses for a wide range of functional food products.

Acid Inhibition on Polyphenol Oxidase and Peroxidase in Processing of Anthocyanin‐Rich Juice and Co‐product Recovery from Purple‐Fleshed Sweetpotatoes

“…(). The TP and TMA concentrations in the extracted juices in this study were comparable with those of the juices from various polyphenol‐rich fruits such as blueberries, blackcurrant, and muscadine grape (Grace et al., ). Pasteurization of the PFSP juices at pH 3.0 in oil bath up to 75 °C to 80 °C for 12 to 30 s as recommended for thermal processing of acidified foods (Breidt et al., ) resulted in 14.7% loss in TMA and had no effect on TP (Table ).…”

“…The combined PFSP juices from the first and second extractions had high yields of TP (1,850 mg/L) and TMA (475 mg/L), which are comparable with a preheating process for anthocyanin extraction from a PFSP variety reported by de Aguiar-Cipriano et al (2015). The TP and TMA concentrations in the extracted juices in this study were comparable with those of the juices from various polyphenol-rich fruits such as blueberries, blackcurrant, and muscadine grape (Grace et al, 2015). Pasteurization of the PFSP juices at pH 3.0 in oil bath up to 75°C to 80°C for 12 to 30 s as recommended for thermal processing of acidified foods (Breidt et al, 2010) resulted in 14.7% loss in TMA and had no effect on TP (Table 4).…”

“…Sweetpotatoes with purple‐fleshed color are rich in beneficial phytochemicals such as phenolic acids and anthocyanins (Grace, Truong, Truong, Raskin, & Lila, ; Lee, Park, Choi, & Jung, ; Oki et al., ). This nutritious vegetable has been processed into various food products including beverages, natural colorants, and polyphenol‐enriched functional food ingredients (Suda et al., ; Truong, Avula, Pecota, & Yencho, ).…”

A Comparison Study of Frying Conditions on Furan Formation in 3 Potato Varieties

“…However, the growing rate of furan concentration of sweet potato and white potato slices was higher than that of purple potato slices. Components contained in the white potato, sweet potato, and purple potato tubers like ascorbic acids, amino acids, vitamins, and polyunsaturated fatty acids, and so on, which are important precursors of furan formation, might affect furan concentration in 3 potato varieties during frying process (Bovell‐Benjamin ; Crews and Castle ; Vranova and Ciesarova ; Mariotti and others ; Grace and others ; Ali and others ).…”

Pea protein isolate characteristics modulate functional properties of pea protein–cranberry polyphenol particles

“…However, these protein–polyphenol interactions have been exploited to develop stable colloidal protein–polyphenol aggregate particles. The particles are utilized as ingredient complexes that bind and concentrate fruit‐ and vegetable‐derived polyphenols to healthy edible protein isolates while excluding excess sugar or water from the polyphenol source and mitigating the astringency typically associated with concentrated flavonoids (Grace et al., 2015). These protein–polyphenol particles have been created with diverse protein and polyphenol sources, including commercially available soy, peanut, whey, rice, pea, and hemp proteins complexed with polyphenols from cranberry, blueberry, muscadine and Concord grapes, cinnamon, green tea, kale, and blackcurrant among others (Grace et al., 2013, 2015; Lila et al., 2017; Plundrich et al., 2014; Roopchand, Kuhn, Krueger et al., 2013; Yousef et al., 2014).…”