Comparative Study on Phenolic Profiles and Antioxidant Activity of Litchi Juice Treated by High Pressure Carbon Dioxide and Thermal Processing

Abstract

The present study compared physicochemical parameters, total phenolic and total flavonoid contents, individual phenolics, and antioxidant activity of litchi juice processed by high pressure carbon dioxide (HPCD), high temperature and ultra high temperature treatments. The results showed that HPCD can retain color of litchi juice better than thermal processing ( p < 0.05), while three processing methods had no influence on pH and total soluble solid in litchi juice. Compared to thermal processing, HPCD processed litchi juice had more total phenolics, total flavonoid and individual phenolics including rutin, (-)-epicatechin and chlorogenic acid ( p < 0.05). Furthermore, the antioxidant activity of litchi juice was analyzed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) assays. The result indicated that HPCD processing can preserve the antioxidant activity better than thermal processing ( p < 0.05). This study suggested that HPCD could be used as an alternative of traditional thermal processing to produce more fresh fruit juice.Keywords: litchi juice, high pressure carbon dioxide, phenolics, antioxidant activity, thermal treatment IntroductionNumerous studies have demonstrated that increased consumption of fruit and vegetable is positively associated with reduced risk of developing chronic diseases, such as cardiovascular disease, diabetes, cancer and Alzheimers's disease (Liu, 2003;Pappas and Schaich, 2009). These health benefits have been attributed in part to the unique phytochemicals of fruit and vegetable (Eberhardt et al., 2000;Liu, 2007).Litchi (Litchi chinensis Sonn.) is a subtropical to tropical fruit of high commercial value in international trade. It becomes one of popular fruit due to its delicious taste and healthy benefits. Phenolic compounds are known as the main active components in litchi fruit, having various bioactive activities, including antioxidant, anticancer, and immunomodulatory activities (Yang et al., 2012;Zhao et al., 2007). Phenolic compounds are also closely related with sensory quality. Until now, most of published literature on the phenolic content and antioxidant activity of litchi fruit focused on its pericarp and seeds (Jiang et al., 2013; Li et al., 2012b; Nagendra *To whom correspondence should be addressed.E-mail: mwzhh@vip.tom.com L. Liu et al. 42 Prasad et al., 2009). Our recent study reported phenolic profiles and antioxidant activity of litchi pulp from different cultivars (Zhang et al., 2013). However, little information is available about the phenolic profiles and antioxidant activity of litchi juice.Litchi is a seasonal fruit and susceptible to spoilage. Therefore, further processing is desirable to extend shelf-life and meet the market demands. Litchi is usually processed into dried fruit or juice. Traditionally, high temperature (HT) short time process is applied in fruit juice processing to prevent microbial growth and to inactivate endogenous enzymes that can cause un...

Reactivity of flavanols: Their fate in physical food processing and recent advances in their analysis by depolymerization

“…However, some systems saturate the medium with other gases instead, such as high‐pressure CO 2 . High‐pressure CO 2 treatment has no significant effect on the polyphenols of litchi juice, whereas high‐temperature treatment results in a significant decrease in (–)‐epicatechin content due to nonenzymatic oxidation (Liu et al., 2015). However, high‐pressure processing may improve the extractability of flavanols and suppress polyphenoloxidase activity.…”

Bioaccessibility of Antioxidants in Blackcurrant Juice after Treatment Using Supercritical Carbon Dioxide

“…Other authors’ studies indicate the effectiveness of the SCCD method in maintaining the high antioxidant capacity of food products [ 42 , 43 , 44 , 45 ]. In the study of red grapefruit juice after SCCD treatment, at several pressure variants and times, no significant differences were detected in the total phenol content, ascorbic acid content, and AC compared to untreated juice [ 42 ].…”

“…The lychee juice treated with SCCD (8 MPa, 36 °C, 120 s) also showed higher AC measured using FRAP and ABTS+• assays, as well as more total phenols and flavonoids compared to thermal treated juice (100 °C, 60 s), and UHT (134 °C, 4 s). Treatment with SCCD supported preservation of the bioactive compounds due to the exclusion of oxygen and a mild temperature [ 45 ].…”

Bioaccessibility of Antioxidants in Blackcurrant Juice After Treatment Using Supercritical Carbon Dioxide

“…This phenomenon may indicate the influence of SCCD on improvement the accessibility of antioxidants for digestion, thanks to which more metabolites were released and they could influence the AC of the fruit juice. Other author studies indicate the effectiveness of the SCCD method in maintaining the high antioxidant capacity of food products [58][59][60][61]. In the study of red grapefruit juice after SCCD treatment, at several pressure variants and times, no significant differences were detected in the total phenol content, ascorbic acid content and AC compared to untreated juice [58].…”

“…The lychee juice treated with SCCD (8 MPa, 36℃, 120 s) also showed higher AC measured using FRAP and ABTS+• assays, as well as more total phenols and flavonoids compared to thermal treated juice (100℃, 60 s), and UHT (134℃, 4 s). Treatment with SCCD supported preservation of the bioactive compounds due to the exclusion of oxygen and a mild temperature [61].…”