Is Eating Raisins Healthy?

High-quality fruit and vegetable characterized by cardiometabolic biomarkers and its relation to major chronic disease risk: resultsfrom 3 prospective United States cohort studies

BACKGROUND

The current guidelines recommend a specified total serving of fruits and vegetables (FV). However, how differences in their nutritional quality influence overall health remains unclear.

OBJECTIVES

To identify high-quality FV using 14 cardiometabolic biomarkers, and assess their consumption, alongside overall FV intake, with chronic disease risk.

METHODS

We used data from 3 prospective cohorts, Health Professionals Follow-up Study, Nurses' Health Study (NHS), and NHSII. Diet was assessed at baseline and updated every 4 y. Biomarker analysis was conducted on 41,714 participants using generalized linear models. Metabolic quality was ascertained by each FV's association with biomarkers. Major chronic disease risk analysis involved 207,241 participants followed for 32 y with Cox proportional hazards models. We also analyzed atherosclerotic cardiovascular disease (ASCVD), type 2 diabetes (T2D), cancer, and chronic obstructive pulmonary disease (COPD) as secondary outcomes.

RESULTS

Of 52 FV items, 19 were identified as high-metabolic quality (top 5: apples/pears, iceberg/head lettuce, raw spinach, alfalfa sprouts, and eggplant/summer squash). In disease risk analysis, 60,712 major chronic disease events were recorded. A higher proportion of high-metabolic quality FV intake was associated with lower chronic disease risk across total FV quantity levels. In each quantity level stratum (quartiles Q1-Q4), comparing the highest to the lowest quality proportion quartiles, the hazard ratio (HR) (95% confidence interval [CI]) were 0.85 (0.81-0.90), 0.86 (0.82-0.90), 0.84 (0.80-0.89), and 0.89 (0.84-0.94), all P-trend < 0.001. Patterns were similar for ASCVD, T2D, and COPD but less consistent for cancer. High total FV intake, if consisting mostly of neutral or low-metabolic quality items, was not associated with lower chronic disease risk. For diabetes specifically, these were associated with significantly higher risk [quantity-Q3, HR: 1.13 (1.05, 1.22); quantity-Q4, HR: 1.17 (1.07, 1.28)].

CONCLUSIONS

Our findings stress the importance of considering both quality and quantity of FV for health, and support dietary guidelines to emphasize high-metabolic quality FV consumption alongside overall intake.

Corinthian Currants Promote the Expression of Paraoxonase-1 and Enhance the Antioxidant Status in Serum and Brain of 5xFAD Mouse Model of Alzheimer's Disease

Paraoxonase-1 (PON1), a serum antioxidant enzyme, has been implicated in Alzheimer's disease (AD) pathogenesis that involves early oxidative damage. Corinthian currants and their components have been shown to display antioxidant and other neuroprotective effects in AD. We evaluated the effect of a Corinthian currant paste-supplemented diet (CurD), provided to 1-month-old 5xFAD mice for 1, 3, and 6 months, on PON1 activity and levels of oxidation markers in serum and the brain of mice as compared to a control diet (ConD) or glucose/fructose-matched diet (GFD). Administration of CurD for 1 month increased PON1 activity and decreased oxidized lipid levels in serum compared to ConD and GFD. Longer-term administration of CurD did not, however, affect serum PON1 activity and oxidized lipid levels. Furthermore, CurD administered for 1 and 3 months, but not for 6 months, increased PON1 activity and decreased free radical levels in the cortex of mice compared to ConD and GFD. To probe the mechanism for the increased PON1 activity in mice, we studied the effect of Corinthian currant polar phenolic extract on PON1 activity secreted by Huh-7 hepatocytes or HEK293 cells transfected with a PON1-expressing plasmid. Incubation of cells with the extract led to a dose-dependent increase of secreted PON1 activity, which was attributed to increased cellular PON1 expression. Collectively, our findings suggest that phenolics in Corinthian currants can increase the hepatic expression and activity of antioxidant enzyme PON1 and that a Corinthian currant-supplemented diet during the early stages of AD in mice reduces brain oxidative stress.

Protective Effects of Medicinal Plant-Based Foods against Diabetes: A Review on Pharmacology, Phytochemistry, and Molecular Mechanisms

Diabetes mellitus (DM) comprises a range of metabolic disorders characterized by high blood glucose levels caused by defects in insulin release, insulin action, or both. DM is a widespread condition that affects a substantial portion of the global population, causing high morbidity and mortality rates. The prevalence of this major public health crisis is predicted to increase in the forthcoming years. Although several drugs are available to manage DM, these are associated with adverse side effects, which limits their use. In underdeveloped countries, where such drugs are often costly and not widely available, many people continue to rely on alternative traditional medicine, including medicinal plants. The latter serves as a source of primary healthcare and plant-based foods in many low- and middle-income countries. Interestingly, many of the phytochemicals they contain have been demonstrated to possess antidiabetic activity such as lowering blood glucose levels, stimulating insulin secretion, and alleviating diabetic complications. Therefore, such plants may provide protective effects that could be used in the management of DM. The purpose of this article was to review the medicinal plant-based foods traditionally used for the management of DM, including their therapeutic effects, pharmacologically active phytoconstituents, and antidiabetic mode of action at the molecular level. It also presents future avenues for research in this field.

New C8-substituted caffeine derivatives as promising antioxidants and cytoprotective agents in human erythrocytes

New structurally diverse groups of C8-substituted caffeine derivatives were synthesized and evaluated for their chemical and biological properties. Mass spectrometry, FT-IR, and NMR characterizations of these derivatives were performed. The cytotoxic activity of the derivatives was estimated in vitro using human red blood cells (RBC) and in silico pharmacokinetic studies. The antioxidant capacity of the compounds was analyzed using a ferrous ion chelating activity assay. The ability of the derivatives to protect RBC from oxidative damage, including the oxidation of hemoglobin to methemoglobin, was assessed using a water-soluble 2,2'-azobis(2-methyl-propionamidine) dihydrochloride (AAPH) as a standard inducer of peroxyl radicals. The level of intracellular oxidative stress was assessed using the fluorescent redox probe 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA). The results indicate that all derivatives are biocompatible compounds with significant antioxidant and cytoprotective potential dependent on their chemical structure. In order to explain the antioxidant and cytoprotective activity of the derivatives, a mechanism of hydrogen atom transfer (HAT), radical adduct formation (RAF), or single electron transfer (SET), as well as the specific interactions of the derivatives with the lipid bilayer of RBC membrane, have been proposed. The results show that selected modifications of the caffeine molecule enhance its antioxidant properties, which expands our knowledge of the structure-activity relationship of caffeine-based cytoprotective compounds.

Temporal Pattern of Neuroinflammation Associated with a Low Glycemic Index Diet in the 5xFAD Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is associated with brain amyloid-β (Aβ) peptide accumulation and neuroinflammation. Currants, a low glycemic index dried fruit, and their components display pleiotropic neuroprotective effects in AD. We examined how diet containing 5% Corinthian currant paste (CurD) administered in 1-month-old 5xFAD mice for 1, 3, and 6 months affects Aβ levels and neuroinflammation in comparison to control diet (ConD) or sugar-matched diet containing 3.5% glucose/fructose (GFD). No change in serum glucose or insulin levels was observed among the three groups. CurD administered for 3 months reduced brain Aβ42 levels in male mice as compared to ConD and GFD, but after 6 months, Aβ42 levels were increased in mice both on CurD and GFD compared to ConD. CurD for 3 months also reduced TNFα and IL-1β levels in male and female mouse cortex homogenates compared to ConD and GFD. However, after 6 months, TNFα levels were increased in cortex homogenates of mice both on CurD and GFD as compared to ConD. A similar pattern was observed for TNFα-expressing cells, mostly co-expressing the microglial marker CD11b, in mouse hippocampus. IL-1β levels were similarly increased in the brain of all groups after 6 months. Furthermore, a time dependent decrease of secreted TNFα levels was found in BV2 microglial cells treated with currant phenolic extract as compared to glucose/fructose solution. Overall, our findings suggest that a short-term currant consumption reduces neuroinflammation in 5xFAD mice as compared to sugar-matched or control diet, but longer-term intake of currant or sugar-matched diet enhances neuroinflammation.

Near-infrared spectroscopy combined with pattern recognition algorithms to quickly classify raisins

With the development of commodity economy, the emergence of fake and shoddy raisin has seriously harmed the interests of consumers and enterprises. To deal with this problem, a classification method combining near-infrared spectroscopy and pattern recognition algorithms were proposed for adulterated raisins. In this study, the experiment was performed by three kinds of raisins in Xinjiang (Hongxiangfei, Manaiti, Munage). After collecting and normalizing the spectral data, we compared the spectra of three kinds of raisins. Next the principal component analysis (PCA) was preformed to compress the dimension of the spectral data, and then classification models including support vector machine (SVM), multiscale fusion convolutional neural network (MCNN) and improved AlexNet were established to identify raisins. The accuracy of SVM, MCNN, and improved AlexNet is 100%, 92.83%, and 97.78% respectively. This study proves that near-infrared spectroscopy combined with pattern recognition is feasible for the raisin inspection.

Towards Recreation of Food Commodities Based on Ancient Texts; The Case of Avyrtake

The aim of the present study was to attempt the recreation of a highly appreciated food commodity of antiquity, called avyrtake, using information derived from ancient texts. The available information included the raw materials, the texture and the taste of the raw materials. On the contrary, the relative proportion of the raw materials as well as the production procedure had to be inferred on the basis of their modern-day use. For that purpose, and based on the above, a mixture of shredded cabbage and leek, salt, pomegranate seeds, raisins, and shredded garlic, as well as ground green cardamon and mustard seeds were pressed into a fermentation jar in order to form a brine and left at 18 °C for fermentation to take place. The latter was driven by lactic acid bacteria, mostly by Lactiplantibacillus plantarum. The final product had a sour character, which matched the organoleptic description available from the ancient texts, and it received high ranks.

Role of dehydration temperature on flavonoids composition and free-form volatile profile of raisins during the drying process

This study investigated the metabolic differences of 'Zicui' raisins produced at different drying temperatures (30 °C, 40 °C and 50 °C). Glucose, fructose, malic acid, shikimic acid and succinic acid contents were the highest in raisins dried at 50 °C. Compared with others, the drying temperature of 40 °C was more conducive to the accumulation of chalcones, dihydroflavones, dihydroflavonols, flavanols, flavonoid carbonosides, proanthocyanidins, and other phenols, while the drying temperature of 30 °C was more conducive to the accumulation of anthocyanins, flavonoid, and flavonols. Most volatile ketones and acids accumulated more in raisins produced at 30 °C, of which the content of 2,6-dimethyl-4-heptanone with sweet odour reached 70.34 μg/L, significantly higher than that in other raisins. Overall, the appropriate drying temperature should be selected according to the demand for specific nutritional or aromatic metabolites during raisins production.

Mechanistic insight into the capacity of natural polar phenolic compounds to abolish Alzheimer's disease-associated pathogenic effects of apoE4 forms

Polar phenols found in plant foods have been suggested to act protectively against pathogenic processes underlying Alzheimer's disease (AD), such as oxidative stress. The major risk factor for AD is apolipoprotein E4 (apoE4) and apoE4 forms can affect AD-related processes. It was shown previously that the hereditary apoE4 mutant apoE4[L28P], as well as the apoE4 fragment apoE4-165, induce neuronal oxidative stress. The effect of polar phenols on AD-related pathogenic functions of apoE4 forms is largely unexplored. The aim was to examine the effect of Corinthian currant polar phenolic extract and specific polar phenols resveratrol, quercetin, kaempferol and epigallocatechin gallate on AD-related functions of apoE4 forms. The polar phenolic extract and the individual compounds restored the viability of human neuroblastoma SK-N-SH cells in the presence of lipoprotein-associated apoE4[L28P] and prevented changes in cellular redox status. Furthermore, resveratrol, quercetin, kaempferol and epigallocatechin gallate prevented redox status changes induced by Aβ42 uptake in SK-N-SH cells treated with lipid-free apoE4[L28P] or apoE4-165. Investigation of the molecular mechanism of action of these polar phenols showed that resveratrol prevented cellular Aβ42 uptake via changes in cell membrane fluidity. Interestingly, kaempferol prevented cellular Aβ42 uptake by apoE4[L28P], but not by apoE4-165, due to a modulating effect on apoE4[L28P] secondary structure and stability. The action of quercetin and epigallocatechin gallate could be attributed to free radical-scavenging or other protective activity. Overall, it is shown for the first time that natural compounds could modify the structure of apoE4 forms and ameliorate AD-related pathogenic effects of apoE4 forms.

The High Content of Quercetin and Catechin in Airen Grape Juice Supports Its Application in Functional Food Production

Ensuring healthy lives and well-being constitutes one of the Sustainable Development Goals of the UN 2030 agenda. Consequently, research into how natural products may promote health is essential for the new generation of nutraceuticals and functional foods that are in high demand today. Grape juice is a natural foodstuff composed of water, sugars, minerals, vitamins and a wide array of polyphenols. Polyphenols are bioactive compounds of great interest due to their antioxidant properties and benefits to health, supporting antimicrobial, anti-aging, and anticarcinogenic activity. The majority of grape juice produced in the world is used for the production of wine, although a small part is used in the food industry, mainly in baby food and sports drinks. The aim of this work is to determine the polyphenol content in the natural and concentrated juice of Airen grapes, the main white grape variety produced in Spain. For this, fresh juices from five grape varietals (Airen, Sauvignon Blanc, Gewürztraminer, Verdejo and Tempranillo) and concentrated Airen juice were analyzed and compared. Results showed similar contents of phenolic acids and stilbenes in all grape varietals studied, although the Airen variety demonstrated a higher concentration of two flavonoids: quercetin and catechin. It can be concluded that the grape juice concentration process negatively affects the stability of these compounds, causing a reduction in the polyphenol content that ranges between 54–71%, with the exception of quercetin and catechin.

Postharvest Dehydration Temperature Modulates the Transcriptomic Programme and Flavonoid Profile of Grape Berries

Raisins are a popular and nutritious snack that is produced through the dehydration of postharvest grape berries under high temperature (HT). However, the response of the endogenous metabolism of white grape varieties to postharvest dehydration under different temperature have not been fully elucidated to date. In this study, the white grape cultivar ‘Xiangfei’ was chosen to investigate the effect of dehydration at 50 °C, 40 °C, and 30 °C on the transcriptomic programme and metabolite profiles of grape berries. Postharvest dehydration promoted the accumulation of soluble sugar components and organic acids in berries. The content of gallic acid and its derivatives increased during the dehydration process and the temperature of 40 °C was the optimal for flavonoids and proanthocyanidins accumulation. High-temperature dehydration stress might promote the accumulation of gallic acid by increasing the expression levels of their biosynthesis related genes and regulating the production of NADP⁺ and NADPH. Compared with that at 30 °C, dehydration at 40 °C accelerated the transcription programme of 7654 genes and induced the continuous upregulation of genes related to the heat stress response and redox homeostasis in each stage. The results of this study indicate that an appropriate dehydration temperature should be selected and applied when producing polyphenols-rich raisins.

Recent Advances in Mycotoxin Analysis and Detection of Mycotoxigenic Fungi in Grapes and Derived Products

Mycotoxins are secondary metabolites of filamentous fungi that can cause toxic effects in human and animal health. Most of the filamentous fungi that produce these mycotoxins belong to four genera, namely, Aspergillus, Penicillium, Fusarium, and Alternaria. Mycotoxigenic fungi, along with mycotoxins, create a constant and serious economic threat for agriculture in many terms, counting product losses due to crop contamination and food spoilage, as well malnutrition when considering nutritional quality degradation. Given the importance of robust and precise diagnostics of mycotoxins and the related producing fungi in the grape food chain, one of the most important agricultural sectors worldwide, the present review initially delivers a comprehensive presentation of mycotoxin reports on grape and derived products, including a wide range of commodities such as fresh grapes, raisins, wine, juices, and other processed products. Next, based on worldwide regulations’ requirements for mycotoxins, and referring to the relative literature, this work presents methodological approaches for mycotoxin determination, and stresses major methods for the detection of fungal species responsible for mycotoxin production. The principle of function and basic technical background on the available analytical and molecular biology techniques developed—including chromatography, mass spectrometry, immunochemical-based assays, biosensors, and molecular assays—is briefly given, and references for their application to grape and derived product testing are highlighted.

A Targeted Approach by High Resolution Mass Spectrometry to Reveal New Compounds in Raisins

Raisins are dried grapes mostly obtained from cultivars of Vitis vinifera L. and are extensively consumed worldwide. They are rich in bioactive compounds such as polyphenols, which are associated with a broad range of health benefits. The aim of the present study was to compare the phenolic profiles of three different raisin varieties (Thompson seedless, Muscat, and sultanas). Total polyphenols (TPs) were evaluated by the Folin–Ciocalteu (F–C) assay and significant differences were observed among all raisin varieties. Furthermore, liquid chromatography coupled with electrospray ionization hybrid linear ion trap quadrupole-Orbitrap-mass spectrometry (LC/ESI-LTQ-Orbitrap-MS) was employed for the comprehensive identification of phenolic constituents. A total of 45 compounds were identified, including hydroxybenzoic and hydroxycinnamic acids, flavanoids, flavonoids, flavonols, flavones, and stilbenoids. The three varieties of raisins showed a similar phenolic profile, although the highest number of phenolic compounds was identified in Muscat raisins owing to the proanthocyanidins extracted from their seeds, while stilbenoids were not detected in the Thompson variety.