Nutritional properties and biological activities of kiwifruit (Actinidia) and kiwifruit products under simulated gastrointestinal in vitro digestion

Transcriptomic analysis reveals ozone treatment delays kiwifruit postharvest softening by modulating cell wall metabolism

Kiwifruit ripening and senescence after harvesting are closely related to its economic value. Transcriptome analysis and biochemical parameters were used to investigate the differences in gene expression levels and the potential regulation of cell wall metabolism in kiwifruit treated with ozone, thereby regulating fruit softening and prolonging postharvest life. Compared to the control group, the activities of the cell wall modification enzyme were lower under ozone treatment, the content of polysaccharide in the cell wall of primary pectin and cellulose was higher, and the content of soluble pectin was lower. Meanwhile, ozone treatment delayed the degradation of the cell wall mesosphere during storage. A total of 20 pectinesterase (PE)-related genes were identified by sequencing analysis. The data analysis and quantitative polymerase chain reaction results confirmed that cell wall modifying enzyme genes played an important role in softening and senescence after harvesting, which may reduce or induce the expression of certain genes affecting cell wall metabolism. Ozone treatment not only regulates active genes such as xyloglucan endo glycosyltransferase/hydrolase, cellulose synthase, polygalacturonase, and PE to maintain the quality of fruit after harvest but also acts synergically with cell wall modifying enzymes to inhibit the degradation of cell wall, resulting in changes in the ultrastructure of cell wall, thereby reducing the hardness of kiwifruit. In addition, according to the results of cis-acting elements, cell wall degradation is also related to downstream hormone signaling, especially PE-related genes. These results provide a theoretical basis for studying the mechanism of firmness and cell wall metabolism difference of kiwifruit and also lay a good foundation for further research.

In vitro anticholinergic and antiglycaemic properties of frost-hardy Actinidia fruit extracts and their polyphenol profile, L-ascorbic acid content and antioxidant capacity

The aim of this study was to investigate the inhibitory effects of Actinidia arguta ('Weiki', 'Skarlet September Kiwi') and Actinidia kolomikta ('Lande') fruit extracts against advanced glycation end-products (AGEs) formation and acetylcholinesterase (AChE) activity. The extracts were also tested regarding polyphenol profile and Lascorbic acid content (UHPLC-DAD-MS), and antioxidant capacity (DPPH, ABTS). 'Scarlet September Kiwi' showed the strongest anti-AGEs activity studied with BSAGLU (IC50 = 2.68) and BSA-MGO (IC50 = 18.06) models. The highest anti-AChE activity was found for the 'Lande' extract (IC50 = 4.56). 'Lande' showed the highest L-ascorbic acid content (8271.96 µg/g dw), ABTS (312.42 µmol TE/g dw) and DPPH (282.01 µmol TE/g dw) values. 'Scarlet September Kiwi' revealed the highest individual phenolics concentration (2321.43 µg/g dw). The contents of (+)-catechin and L-ascorbic acid were significantly correlated with anti-AChE activity. This research sheds new light on the bioactivity of Actinidia arguta and Actinidia kolomikta fruit elucidating the role of (+)-catechin and L-ascorbic acid in prevention of Alzheimer's disease.

Dried Fruits: Bioactives, Effects on Gut Microbiota, and Possible Health Benefits—An Update

Dried fruits contain many bioactive compounds broadly classified as phytochemicals including phenolics, flavonoids, carotenoids, proanthocyanidins, stilbenes, chalcones/dihydrochalcones, and phytoestrogens. These compounds have antioxidant effects that may benefit health. Dried fruits are also a diverse group of foods with varying fibre contents. The evaluation of the biological activity of these bioactive compounds, including their bioaccessibility and bioavailability, may contribute to the understanding of the health effects of dried fruits. Limited evidence suggests that dried fruits (raisins, cranberries, dates, and prunes) affect human gut microbiota composition in a potentially beneficial manner (in terms of effects on Bifidobacteria, Faecalibacterium prausnitzii, Lactobacillus, Ruminococcaceae, Klebsiella spp., and Prevotella spp.). There is little epidemiological evidence about the association of dried fruit consumption with cardiovascular disease incidence and mortality, as well as the risk of type 2 diabetes or obesity. Clinical trial evidence for the effects of dried fruit consumption on cardiovascular risk factors, including glycaemic control, is mixed. Clinical trial evidence suggests prunes might preserve bone mineral density in postmenopausal women. Consumption of dried fruits is associated with higher-quality diets. Studies are needed to increase our understanding of the health effects of dried fruits and the underlying biological mechanisms.

Bioaccessibility of phenolic compounds using the standardized INFOGEST protocol: A narrative review

The INFOGEST protocol creation was a watershed for phenolic bioaccessibility studies. Because of this important initiative to standardize bioaccessibility studies, data comparisons between different laboratories are now expedited. It has been eight years since the INFOGEST protocol creation, and three from the latest update. However, the current status in terms of phenolic bioaccessibility and how far different laboratories are from reaching a consensus are still unrevealed. In this sense, this narrative review considered an evaluation of different studies that applied the INFOGEST protocol to investigate the bioaccessibility of phenolic compounds. The central objective was to compile the main findings and consensus and to identify possible gaps and future opportunities. This approach intends to further facilitate the use of this protocol by professionals in the field of food science and technology and related areas, generating a reflection on the actual level of standardization of the method. Despite the differences in phenolic compounds from diverse food matrices, and their peculiar behavior, some trends could be elucidated, in terms of phenolic release, stability, and/or transformation upon in vivo digestion. In contrast, there was no general consensus regarding sample preparation, how to report results and the form to calculate bioaccessibility, making it difficult to compare different studies. There is still a long road to effectively standardize the results obtained for phenolic bioaccessibility using the INFOGEST protocol, which is also an opportunity in terms of food analysis that can impact the food industry, especially for the development of nutraceuticals and functional foods.

Analysis of the Aroma Chemical Composition of Commonly Planted Kiwifruit Cultivars in China

The aroma chemical composition of commonly planted kiwifruit cultivars in China was analyzed. The combination of 2-octanone with 3-octanone was the most suitable dual internal standard for quantitative analysis in GC-MS. A total of 172 aroma components in 23 kiwifruit cultivars were detected, and ethyl butanoate, (E)-2-hexen-1-ol, and (E)-2-hexenal could be considered the core aroma components in kiwifruit, but still need further confirmation using Sensomics. E-nose could effectively distinguish different cultivars of kiwifruit. Clustering based on GC-MS and E-nose results tends to be consistent and demonstrate a certain degree of similarity. Kiwifruit cultivars with different flesh colors cannot be effectively distinguished by their aroma chemical compositions. Different species of kiwifruit can be distinguished to some extent by their aroma chemical compositions, but the effect was not satisfactory. These results could prove valuable in the breeding, planting, and marketing of kiwifruits.

Eco-friendly management of postharvest fungal decays in kiwifruit

Kiwifruit is purchased by consumers worldwide and is increasing in demand. Unfortunately, kiwifruit is susceptible to postharvest decay caused by a variety of fungal pathogens, including Botrytis cinerea, Penicillium expansum, Alternaria alternata, Botryosphaeria dothidea, and Diaporthe spp. Among these pathogens, B. cinerea is the most prevalent and devastating. Infections by these fungal pathogens result in a deterioration in fruit quality and a reduction in marketable yield. Eco-friendly methods to control kiwifruit postharvest decay have been explored as alternatives to the use of synthetic fungicides. In this review, we provide an overview and discuss the virulence and pathogenesis of fungi that are causal agents of kiwifruit decay, especially B. cinerea, including recent molecular and genomic studies. Advances in pre- and postharvest measures for postharvest decay management, including biological control, physical applications, the use of natural compounds and plant hormones, and the use of combined methods, are also reviewed. Eco-friendly control measures are a critical component of an integrated management approach for sustainable production of kiwifruit. The need for further research on the use of microbial consortia for the management of postharvest diseases of kiwifruit is also discussed.

Characterization of Phenolics in Rejected Kiwifruit and Their Antioxidant Potential

Kiwifruit hold significant nutritional value and are a good source of antioxidants due to their diverse range of bioactive compounds. Kiwifruit waste is generated throughout the food supply chain, particularly during transportation and storage. Kiwifruit rejected from the retail market due to unfavorable appearance still possess potential economic value as kiwifruit are abundant in phenolic compounds. The present work studied the phenolic profile and antioxidant potential of rejected kiwifruit, including SunGold (Actinidia chinensis), Hayward (Actinidia deliciosa), and round organic Hayward (Actinidia deliciosa). Regarding phenolics estimation, SunGold possessed the highest TPC (0.72 ± 0.01 mg GAE/g), while Hayward exhibited the highest TFC (0.05 ± 0.09 mg QE/g). In antioxidant assays, SunGold showed the highest antioxidant activities in DPPH (0.31 ± 0.35 mg AAE/g), FRAP (0.48 ± 0.04 mg AAE/g), ABTS (0.69 ± 0.07 mg AAE/g), •OH-RSA (0.07 ± 0.03 mg AAE/g) assays, and FICA (0.19 ± 0.07 mg EDTA/g), whereas Hayward showed the highest RPA (0.09 ± 0.02 mg AAE/g) and TAC (0.57 ± 0.04 mg AAE/g). Separation and characterization of phenolics were conducted using LC-ESI-QTOF-MS/MS. A total of 97 phenolics were tentatively characterized from rejected SunGold (71 phenolics), Hayward (55 phenolics), and round organic Hayward (9 phenolics). Hydroxycinnamic acids and flavonols were the most common phenolics characterized in the three samples. The quantitative analysis was conducted by HPLC-PDA and found that chlorogenic acid (23.98 ± 0.95 mg/g), catechin (23.24 ± 1.16 mg/g), and quercetin (24.59 ± 1.23 mg/g) were the most abundant phenolics present in the rejected kiwifruit samples. The notable presence of phenolic compounds and their corresponding antioxidant capacities indicate the potential value of rescuing rejected kiwifruit for further utilization and commercial exploitation.

Kiwifruit (Actinidia spp.): A review of chemical diversity and biological activities

Kiwifruit (Actinidia spp.) is a commercially important fruit crop. Various species and cultivars, non-fruit plant parts, and agricultural and processing wastes are underutilized. A broad-scoped review of kiwifruit guides further innovative applications. Different kiwifruit varieties and edible and nonedible parts varied in the composition of dietary nutrients including polyphenols, vitamins, dietary fiber, and functional ingredients, such as starch and protease and bioactive phytochemicals. Kiwifruits exhibit antioxidative, antiproliferative, antiinflammatory, antimicrobial, antihypertensive, antihypercholesterolemic, neuroprotective, antiobese properties and promote gut health. Clinically significant effects of kiwifruit on prevention and/or treatment of major chronic diseases are not yet evident. Varieties and plant parts, extraction, analytical and processing methods affect the physicochemical and biological properties of kiwifruit-derived ingredients. Allergens, mycotoxins, pesticides and heavy metals are the chemical hazards of kiwifruits. Future research should be focused on sustainable uses of underutilized resources as functional ingredients, bioactive compound purification, composition-activity relationships, and physiological mechanisms and clinical significance of kiwifruits.

Insight into Polyphenol and Gut Microbiota Crosstalk: Are Their Metabolites the Key to Understand Protective Effects against Metabolic Disorders?

Lifestyle factors, especially diet and nutrition, are currently regarded as essential avenues to decrease modern-day cardiometabolic disorders (CMD), including obesity, metabolic syndrome, type 2 diabetes, and atherosclerosis. Many groups around the world attribute these trends, at least partially, to bioactive plant polyphenols given their anti-oxidant and anti-inflammatory actions. In fact, polyphenols can prevent or reverse the progression of disease processes through many distinct mechanisms. In particular, the crosstalk between polyphenols and gut microbiota, recently unveiled thanks to DNA-based tools and next generation sequencing, unravelled the central regulatory role of dietary polyphenols and their intestinal micro-ecology metabolites on the host energy metabolism and related illnesses. The objectives of this review are to: (1) provide an understanding of classification, structure, and bioavailability of dietary polyphenols; (2) underline their metabolism by gut microbiota; (3) highlight their prebiotic effects on microflora; (4) discuss the multifaceted roles of their metabolites in CMD while shedding light on the mechanisms of action; and (5) underscore their ability to initiate host epigenetic regulation. In sum, the review clearly documents whether dietary polyphenols and micro-ecology favorably interact to promote multiple physiological functions on human organism.

Comparative Analysis of Physicochemical Characteristics, Nutritional and Functional Components and Antioxidant Capacity of Fifteen Kiwifruit (Actinidia) Cultivars-Comparative Analysis of Fifteen Kiwifruit (Actinidia) Cultivars

Physicochemical characteristics, nutritional and functional components, and the antioxidant capacity of 15 kinds of domestic and imported kiwifruit in China were studied. Kiwifruit was classified according to flesh color or species, and the differences were analyzed and compared. Results demonstrated Ruiyu had the highest sugar-acid ratio, and Hongshi No.2 was an excellent cultivar with strong antioxidant capacity. TPC (total polyphenol content) and AAC (ascorbic acid content) showed a significant positive correlation. TPC was the greatest antioxidant contributor in the DPPH and FRAP assays. The sugar-acid ratio and TFC (total flavonoids content) in red-fleshed kiwifruit were significantly higher than those in yellow-fleshed and green-fleshed ones. The composition of free amino acids had a tendency to distinguish A. deliciosa and A. chinensis, but this needs further verification. In addition, the contents of mineral elements, folic acid and L-5-methyltetrahydrofolate were also analyzed. Generally, kiwifruit contains comprehensive nutrients and has strong antioxidant capacity. Cultivar is one of the main factors affecting nutritional and functional properties and antioxidant capacity.

Transcriptomics integrated with metabolomics reveals the effect of regulated deficit irrigation on anthocyanin biosynthesis in Cabernet Sauvignon grape berries

Regulated deficit irrigation (RDI) is a new type of water-saving irrigation technology developed in recent years which was well suited to arid and semi-arid grape plant areas. The anthocyanin synthesis of grapes under RDI was revealed through omics in this study. RDI slightly decreased the hundred-grain weight and increased the soluble solid content, juice pH, reducing sugar content, and total anthocyanin content. Meanwhile, the total acid content decreased before ripening. Transcriptomics and metabolomics analyses revealed that large numbers of differentially expressed genes (DEGs) and significantly changed metabolites (SCMs) were filtered in the RDI groups. RDI1 with 30% ETc upregulated 7 related gene expression levels in the anthocyanin biosynthetic pathway and also increased some metabolites contents. Eventually, the contents of most monomeric anthocyanins in the RDI groups were increased, and the proportion of Mv increased in the ripe grapes of the RDI groups. In all, RDI is a useful water-saving irrigation method which could also increase anthocyanin content in grapes.

Letting wine polyphenols functional: Estimation of wine polyphenols bioaccessibility under different drinking amount and drinking patterns

Effects of drinking amount and patterns of wine on the digestive characteristics and bioaccessibility of wine polyphenols under in vitro gastrointestinal digestion were investigated. Wine polyphenols released well during mouth and stomach digestion, and the release rates in the "serum-available" fraction, "colon-available" fraction, and after the colon were much lower. Red wine showed a higher biological activity than white wine, but white wine had a better bioaccessibility than red wine, especially under binge drinking. The bioaccessibility of most polyphenols decreased as the drinking amount increased, indicating that drinking larger volumes of wine did not increase the bioaccessibility of polyphenols. Additionally, the relevant biological activities did not increase as the drinking amount increased. Drinking after a meal showed significantly better results than drinking before a meal in most of the tests. Hence, in order to let wine polyphenols play its functional for human health, there still need a moderate consumption amount of wine and drinking after meal is better.