Persimmon peel deastringency by CO₂ and ethanol combination: Product quality and polyphenols bioavailability

Abstract

Persimmons are popular worldwide owning to their unique flavor and nutritional value, while for the astringent cultivars, deastringency treatment is needed before processing. The current deastringency methods are limited to CO2 and ethanol. The aim of this work was to select optimal deastringency methods and assess the bioavailability of polyphenols in persimmon peels treated with 12 different combination of CO2 and ethanol. The level of soluble and insoluble tannins, total polyphenols bioaccessibility, antioxidant properties, color, and soluble solids were also determined. Results indicated that soluble tannin contents decreased with increasing ethanol concentration, and with an increase in carbon dioxide concentration, the insoluble tannins content increased. Application of 30% ethanol solution and 80% carbon dioxide for 24 hr has a best deastringency effect, while this treatment does not show good phenolics bioaccessibility and antioxidant activity. Therefore, the combination of 30% ethanol solution with 70% CO2 fumigation for 24 hr at 10 °C is the best deastringency method. Practical applications This project invented a novel deastringency method by CO2 and ethanol combination, with a feature of applying to lower temperature. The aim of this work was to select optimal deastringency methods and assess the bioavailability of polyphenols in persimmon peels treated with 12 different combination of CO2 and ethanol.

Effect of ensiling persimmon peel and grape pomace as tannin‐rich byproduct feeds on their chemical composition and in vitro rumen fermentation

“…The soluble tannin content (9.1 g/kg fresh matter) of the PP used in the present study was higher than that reported (3.8 g/kg fresh matter) by Liu et al (2018), but was within the range of values for persimmon fruits reported by Taira et al (1998). Previous studies have reported total phenolics and total tannin contents in grape pomaces of 22.7 and 15.6 g/kg DM, respectively (Alipour & Rouzbehan, 2007;Pirmohammadi et al, 2007), which differed from the values found in the present study.…”

“…The soluble tannin content (9.1 g/kg fresh matter) of the PP used in the present study was higher than that reported (3.8 g/kg fresh matter) by Liu et al. (2018), but was within the range of values for persimmon fruits reported by Taira et al. (1998).…”

“…Although the total tannin content in each byproduct was steady during the first 4 weeks of ensiling, the contents of soluble and insoluble tannin in PP changed dramatically. The increase in insoluble tannin in PP during the first 2 weeks of ensiling probably reflected the insolubilization reaction of tannin which occurs during the de‐astringency procedures for persimmon fruit which involve using ethanol, CO 2 , or a combination of both (Liu et al., 2018; Taira et al., 1998) because the ensiling condition exposed by ethanol and CO 2 in silos is similar to that of the de‐astringency treatment. In the de‐astringency treatment, ethanol or CO 2 forms acetaldehyde which polymerizes (insolubilize) the tannins by condensation (Tanaka et al., 2018).…”

“…Previous studies have shown that ensiling grape pomace decreased its tannin content but negatively influenced ruminal fermentation (Alipour & Rouzbehan, 2010). Besides, the tannins in persimmon fruits are insolubilized by the deastringency treatment with ethanol and CO 2 (Liu et al., 2018; Yamada et al., 2002). Thus, ensiling treatment would affect the property of tannins in PP as well because CO 2 and ethanol are produced by microbial fermentation during ensiling process.…”

In Vitro and In Vivo Digestion of Persimmon and Derived Products: A Review

“…Liu et al [ 30 ] selected optimal deastringency methods and evaluated the bioaccessibility of polyphenols in Yongding persimmon peels treated with 12 combinations of CO 2 and ethanol. EP and NEP content after the deastringency treatments as well as the antioxidant capacity and bioaccessibility of the EP after in vitro digestion, were determined.…”