Synthesis and applications of epicatechin and epiafzelechin derivatives from proanthocyanidins

Ph.DDOCTOR OF PHILOSOPH

Editorial: Exploring sustainable strategies for active compounds from low-quality crops: Extraction, package, and development

With the explosive growth of the global population and the rapid development of agriculture and food technology, people have shown a huge demand for high-quality and diverse food (Tripathi et al., 2019), followed by the rapid development and expansion of the food processing industry. However, this also raises new problems. To pursue products with higher nutritional value on the basis of ensuring cost stability and work efficiency, food enterprises will produce a series of low-quality by-products in each link of the food industry. They directly waste numerous low-quality raw materials, and of course, numerous nutrients contained in them can also be wasted (Spiker et al., 2017). Considering the large global population base, how to realize the value-added of low-quality crops has become a hot topic in recent years (AliAkbari et al., 2021). In view of this, many researchers have put forward some ideas, such as using low-value crops as biomass energy (Jin et al., 2018; Ganesh et al., 2022), developing New foods (Ganesh et al., 2022), using advanced processing technology to produce high value-added products (Kewuyemi et al., 2022) and improving the extraction process of active substances (Putnik et al., 2018) etc. One strategy we have noticed is to extract and utilize the nutrient-active substances contained in these low-quality crops (Kita et al., 2023), to realize the reuse of extracted materials. In the future, we can not only realize the value-added of low-quality crops, but also use these extracted active substances to develop more functional foods to meet the needs of consumers, and even try to solve some technical problems faced by the current food industry to obtain products with higher market value. This paper analyzes the content of the four latest related studies to gain insight into the significance of these research results for the food processing industry and functional food development, and to provide theoretical guidance for future research directions

Antioxidant activities of fractions from longan pericarps

The antioxidant activities of ethanolic crude extract (LPCE) and its four different solvent sub-fractions (namely, diethyl ether fraction (LPDF), ethyl acetate fraction (LPEF), n-butyl alcohol fraction (LPBF) and residue fraction (LPR)) from longan pericarps were investigated employing various systems including 2,2-diphenyl-1-picrylhydrazyl (DPPH)/ 2,2'-amino-di(2-ethyl-benzothiazoline sulphonic acid-6)ammonium salt (ABTS)/hydroxyl radical scavenging activity, total phenolic content and reducing power. Each extract showed concentration-dependent antioxidant activity. LPEF showed the highest scavenging activity against DPPH, ABTS and hydroxyl radicals with EC50 values of 0.506, 0.228 and 4.489 mg/mL, respectively. LPEF showed the highest reducing power with EC50 values of 0.253 mg/mL. The next was LPDF with EC50 values of 0.260 mg/mL. LPEF possessed the highest total phenolic content (230.816 mg/g, expressed as gallic acid equivalents), followed by LPDF, LPBF, LPCE and LPR. The results suggested that longan pericarp fractions possessed significant antioxidant activities and could be a promising source of natural antioxidant

Facial Fabrication of Large-Scale SERS-Active Substrate Based on Self-Assembled Monolayer of Silver Nanoparticles on CTAB-Modified Silicon for Analytical Applications

Surface-enhanced Raman spectroscopy (SERS) has been proven to be a promising analytical technique with sensitivity at the single-molecule level. However, one of the key problems preventing its real-world application lies in the great challenges that are encountered in the preparation of large-scale, reproducible, and highly sensitive SERS-active substrates. In this work, a new strategy is developed to fabricate an Ag collide SERS substrate by using cetyltrimethylammonium bromide (CTAB) as a connection agent. The developed SERS substrate can be developed on a large scale and is highly efficient, and it has high-density “hot spots” that enhance the yield enormously. We employed 4-methylbenzenethiol(4-MBT) as the SERS probe due to the strong Ag–S linkage. The SERS enhancement factor (EF) was calculated to be ~2.6 × 106. The efficacy of the proposed substrate is demonstrated for the detection of malachite green (MG) as an example. The limit of detection (LOD) for the MG assay is brought down to 1.0 × 10−11 M, and the relative standard deviation (RSD) for the intensity of the main Raman vibration modes (1620, 1038 cm−1) is less than 20%

Antioxidant activities of kombucha prepared from three different substrates and changes in content of probiotics during storage

Kombucha is a health-promoting fermented beverage worldwide. The present study compared the free-radical scavenging abilities and total reducing power (TRP) of kombucha prepared from low-cost green tea (LGTK), black tea (BTK), and tea powder (TPK). LGTK had the highest scavenging abilities against 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion and hydroxyl radicals, while BTK showed the highest TRP. Changes in content of probiotics in LGTK were investigated during storage as well. The number of acetic acid bacteria decreased moderately up to 10 days of storage. The number of lactic acid bacteria (LAB) decreased significantly, and their survival rate was only 0.98% at the 8th day of storage

Phase Noise Cancelation Based on Polarization Modulation for Massive MIMO-OFDM Systems

In massive multiple-input multiple-output (MIMO) systems, phase noise introduced by oscillators can cause severe performance loss. It leads to common phase error and intercarrier interference in massive MIMO-OFDM uplink. To solve the issue, a novel phase noise cancelation scheme based on polarization modulation for the massive MIMO-OFDM system is proposed. We first introduce the polarization modulation (PM) exploited in massive MIMO-OFDM uplink. Then, by exploiting the zero-forcing detection, we analyze the asymptotically ICI and the distribution of the transformed noise under different XPD values. Furthermore, we demonstrate that phase noise can be asymptotically canceled and only the transformed additive white Gaussian noise exists as the number of antennas at the base station is very large. Moreover, we derive the instantaneous signal-to-noise ratio (SNR) on each subcarrier and analyze the ergodic capacity. To increase the ergodic capacity performance further, a joint modulation scheme combining the PM and 2PSK is proposed and the ergodic capacity performance of the joint modulation is discussed. The simulation results show that the proposed scheme can effectively mitigate phase noise and achieve a higher ergodic capacity