Effect of thermal processing on phenolic profiles and antioxidant activities in Castanea mollissima

Abstract

The effect of three domestic thermal processing methods on chestnut fruit was analysed in this study. By evaluating the changes of the contents of free and bound phenolic profiles as well as the antioxidant activity in chestnut fruit, our study indicated that steaming could better preserve and enhance the level of phenolics and flavonoids in chestnut fruit and thus brought to a higher antioxidant activity. Microwaving could increase the phenolic content and the antioxidant activity of chestnut fruits within a short time, while blanching caused a decrease of flavonoid contents. In addition, our research suggested that there was formation of new phenolics in chestnut fruit, which were discovered during thermal processing because of the increases of bound phenolics after processing. Therefore, the potential of chestnut fruits to be developed as a kind of functional food could be highly expected.

Phytochemical Profiles and Cellular Antioxidant Activities in Chestnut (Castanea mollissima BL.) Kernels of Five Different Cultivars

“…On the other hand, to our knowledge, most studies on chestnut mainly focused on free phytochemicals, while bound phytochemicals and its contributions to the total phenolics and total antioxidant activity were overlooked [16,22,23,28]. As detected both free and bound phenolics by our research team, the total phenolics in chestnut kernel (fresh or treated) was found around 40-90 mg GAE/100 g FW and the value was much higher after steaming treatment than fresh chestnut kernel [2,22,24]. In this study, the contents of total phenolics varied from 40 to 60 mg GAE/100 g FW in five different chestnut cultivars, and the bound phenolics contributed about 31-43% to total phenolics (Figure 1), which might be overlooked in previous studies.…”

“…Epidemiological studies have demonstrated the significance of phytochemicals, especially phenolic compounds, to human health due to their additive and synergistic effects on radicals scavenging [7][8][9]. Recent years, more studies focused on phytochemical profiles and antioxidant activities of fruits [10][11][12][13][14][15], and also the nuts [16,17], such as walnut [18,19], pistachio [20,21], and chestnut [1,3,[22][23][24][25].…”

Comparison of releasing bound phenolic acids from wheat bran by fermentation of three Aspergillus species

“…Some more effective methods have been developed, such as acidic and alkalic hydrolysis, steam explosion, microwave-assisted extraction and ultrasound-assisted extraction. However, these harsh reaction conditions can destroy the structure of some phenolic acids, and high energy consumption makes these methods environmentally unfriendly and very costly (Martins et al, 2011;Li et al, 2016;Liu et al, 2016Liu et al, , 2017. Fermentation by microorganisms is attracting increasing attention owing to its effectiveness and environmental friendliness, and has been reported to release phenolic acids effectively from materials such as soybean products, rye bran, finger millet and wholemeal rye sourdoughs (Hole et al, 2012;Gan et al, 2016;Koistinen et al, 2017;Peng et al, 2017).…”

Effects of different solvents on total phenolic and total anthocyanin contents of Clitoria ternatea L. petal and their anti‐cholesterol oxidation capabilities

“…In this study, compounds such as kaempferol 3‐neohesperidoside donated hydrogen molecules to organic nitrogen radicals (DPPH) and contributed to the free radical scavenging activity. In DW extracts, both TPC and DPPH antioxidant capacity (Table ) were consistent up to 12 h, then showed a significant reduction at 24 h, indicating that their effectiveness was directly related to total amount of polyphenols (Alali et al ., ; Liu et al ., ). Contrary to the DW and M treatments, DPPH values of DWM extracts did not show significant differences across all soaking times.…”

“…In aqueous CT petal extracts, bioactive compounds such as 3,5-delphinidin glucoside, 3b-delphinidin glucoside, 3b-malvidin glucoside, kaempferol, q-coumaric acid and six types of ternatins: A1, A2, B1, B2, D1 and D2 contribute to antioxidant activity (Chayaratanasin et al, 2015) and anticancer activity (Shen et al, 2016). Therefore, it is necessary to determine the extraction conditions -including pH, soaking time and solvent-typethat give a high yield of bioactive compounds from CT petals, as higher amounts of phenolics typically relate to greater antioxidant capacity (Liu et al, 2017). Because CT petals can be consumed fresh without concern of toxicity ( Boonsong et al, 2011), their extracts can be further investigated for possible food applications.…”