Evaluation of the Antioxidant Activity, Deodorizing Effect, and Antibacterial Activity of 'Porotan' Chestnut By-Products and Establishment of a Compound Paper

Effects of chestnut shell extract and citric acid on the properties of navel orange pomace/chitosan composite films

The improper use of citrus peel and nondegradable plastic film can cause substantial issues, such as environmental pollution and resource waste. Herein, navel orange pomace powder (NOPP) and chitosan (CS) were used as the raw material and film-forming additive, respectively, to prepare biobased composite films. Chestnut shell extract (CHE) and citric acid (CA) were added to the prepared NOPP/CS biobased multifunctional films. Based on ensuring the tensile strength of the film above 10 MPa, the elongation at break of the film can be increased from 19.11 % to 34.93 %, the water contact angle can reach 60°, and the water vapor transmittance can be significantly reduced to approximately 1.1 × 10-10 gs-1m-1Pa-1. Additionally, the antibacterial ability and antioxidant capacity of the composite film were improved. We observed that the multifunctional film could significantly inhibit the browning of fresh-cut apples, where the browning index was maintained between 60 and 65, which was 25 % lower than that of the control. The newly developed film therefore possesses the potential to replace the traditional plastic cling film. This research contributes to the literature regarding the source of raw materials for biobased materials and highlights the value of navel orange processing by-products.

Effect of Addition of Tannin Extract from Underutilized Resources on Allergenic Proteins, Color and Textural Properties of Egg White Gels

Tannins, present in numerous plants, exhibit a binding affinity for proteins. In this study, we aimed to exploit this property to reduce the concentration of allergenic egg white proteins. Tannins were extracted, using hot water, from the lyophilized powder of underutilized resources, such as chestnut inner skin (CIS), young persimmon fruit (YPF), and bayberry leaves (BBLs). These extracts were then incorporated into an egg white solution (EWS) to generate an egg white gel (EWG). Allergen reduction efficacy was assessed using electrophoresis and ELISA. Our findings revealed a substantial reduction in allergenic proteins across all EWGs containing a 50% tannin extract. Notably, CIS and BBL exhibited exceptional efficacy in reducing low allergen levels. The addition of tannin extract resulted in an increase in the total polyphenol content of the EWG, with the order of effectiveness being CIS > YPF > BBL. Minimal color alteration was observed in the BBL-infused EWG compared to the other sources. Additionally, the introduction of tannin extract heightened the hardness stress, with BBL demonstrating the most significant effect, followed by CIS and YPF. In conclusion, incorporating tannin extract during EWG preparation was found to decrease the concentration of allergenic proteins while enhancing antioxidant properties and hardness stress, with BBL being particularly effective in preventing color changes in EWG.

Low Allergenicity in Processed Wheat Flour Products Using Tannins from Agri-Food Wastes

The present study aimed to investigate the effect of the addition of tannins from unutilized resources on wheat allergen reduction, antioxidant properties, and quality by substituting 3%, 5%, and 10% of the flour with chestnut inner skin (CIS) and young persimmon fruit (YPF) powders to produce cookies. The enzyme-linked immunosorbent assay and Western blotting showed significantly lower wheat allergen content in CIS- or YPF-substituted cookies than in control cookies, and this effect was pronounced for CIS-substituted cookies. In addition, the tannin content and antioxidant properties of the CIS- or YPF-substituted cookies were markedly higher than those of the control cookies. Quality analysis of the CIS- and YPF-substituted cookies showed that the specific volume and spread factor, which are quality indicators for cookies, were slightly lower in the CIS- and YPF-substituted cookies than in the control cookies. Compared to the control, CIS substitution did not affect the breaking stress and total energy values of the cookies; however, YPF substitution at 10% increased these values. Color was also affected by the addition of CIS and YPF. The results suggest that the addition of CIS and YPF can reduce wheat allergens in cookies and improve tannin content and antioxidant properties.

Chestnut inner shell extract inhibits viral entry of porcine epidemic diarrhea virus and other coronaviruses in vitro

Porcine epidemic diarrhea virus (PEDV) is a coronavirus that causes acute diarrhea in suckling piglets. Although vaccines are able to reduce the incidence of PEDV infection, outbreaks of PEDV continue to be reported worldwide and cause serious economic losses in the swine industry. To identify novel antiviral sources, we identified the chestnut (Castanea crenata) inner shell (CIS) as a natural material with activity against PEDV infection in vitro. The ethanol fractions of CIS extracts potently inhibited PEDV infection with an IC90 of 30 μg/ml. Further investigation of the virus lifecycle demonstrated that CIS extract particularly targeted the early stages of PEDV infection by blocking viral attachment and membrane fusion at rates of 80~90%. In addition, CIS extract addition reduced the viral entry of other members of the Coronaviridae family. Our data demonstrated that CIS extract inhibited PEDV infection by blocking cell entry in vitro and suggest that CIS extract is a new prophylactic and therapeutic agent against PEDV and other coronavirus infections.

Recovery of High Value-Added Compounds from Food By-Product

The agri-food industry generates large quantities of by-products, both of animal and vegetable origin, which are currently discarded or destined to low-value-added applications [...].

Metabolite Profiling of Chestnut (Castanea crenata) According to Origin and Harvest Time Using 1H NMR Spectroscopy

Chestnuts are an important food crop commonly used as a food ingredient due to their nutritional properties and potential health benefits. In Korea, chestnuts have been crossbred to develop cultivars with insect resistance and high productivity, producing multiple chestnut varieties. This study classified 17 Castanea crenata cultivars produced in Korea according to origin and harvest time and determined the metabolites in chestnut kernels using ¹H nuclear magnetic resonance spectroscopy. The 17 C. crenata cultivars were divided into four groups based on their geographic origin: Korean native, Korean hybrid, Japanese native, and Japanese hybrid. The cultivars were also divided into three groups depending on their harvest period: early-ripening cultivar, mid-ripening cultivar, and late-ripening cultivar. The partial least squares-discriminant analysis score plot revealed differences among the groups. Identified metabolites, including amino acids, organic acids, and sugars, contributed to discriminating the origin and harvest time of the C. crenata chestnut kernels. Significant differences were observed, mainly in amino acids, which suggests that the composition of amino acids is one factor influenced by both the origin and harvest time of C. crenata. These results are useful to both growers and breeders because they identify the nutritional and metabolic characteristics of each C. crenata cultivar.