Polyphenols are the predominant ingredients in apple seeds. However, few data are available on the phenolic profile or antioxidant activity in apple seeds in previous researches. In this study, low-molecular-weight phenolic compounds and antioxidant activity in seeds, peels, and flesh of seven apple cultivars grown in northwest China were measured and analyzed using HPLC and FRAP, DPPH, ABTS assays, respectively. HPLC analysis revealed phloridzin as the dominant phenolic compound in the seeds with its contents being 240.45-864.42 mg/100 gDW. Total phenolic content (TPC) measured by the Folin-Ciocalteu assay in apple seed extracts of seven cultivars ranged from 5.74 (Golden Delicious) to 17.44 (Honeycrisp) mgGAE/gDW. Apple seeds showed higher antioxidant activity than peels or flesh; antioxidant activity in seeds varied from 57.59 to 397.70 μM Trolox equivalents (TE)/g FW for FRAP, from 37.56 to 64.31 μM TE/g FW for DPPH, and from 220.52 to 708.02 μM TE/g FW for ABTS. TPC in apple seeds was significantly correlated with all three assays. Principal component analysis (PCA) indicated that Honeycrisp was characterized with high contents of total polyphenols and phloridzin. Our findings suggest that phenolic extracts from apple seeds have good commercial potential as a promising antioxidant for use in food or cosmetics.
BackgroundSynthetic antioxidants and antimicrobials are losing ground to their natural counterparts and therefore, the food industry has motivated to seek other natural alternatives. Apple pomace, a by-product in the processing of apples, is rich in polyphenols, and plant polyphenols have been used as food additives owing to their strong antioxidant and antimicrobial properties. The goal of this study was to screen the individual polyphenols with antioxidant and antimicrobial activities from the extracts (methanol, ethanol, acetone, ethyl acetate, and chloroform) of Golden Delicious pomace.ResultsFirst, the polyphenolic compounds (total phenol content, TPC; total flavonoids, TFD; total flavanols, TFL) and antioxidant activities (AAs) with four assays (ferric reducing antioxidant power, FRAP; 1,1-diphenyl-2-picryhydrazyl radical scavenging capacity assay, DRSC; hydroxyl radical averting capacity assay, HORAC; oxygen radical absorbance capacity assay, ORAC) were analyzed. The results showed a significant positive correlation (P < 0.05) between AAs and TFD. Ethyl acetate extract (EAE) exhibited the highest TFD with a concentration of 1.85 mg RE/g powder (expressed as rutin equivalents), and the highest AAs (expressed as butylated hydroxytoluene (BHT) equivalents) with 2.07 mg BHT/g powder for FRAP, 3.05 mg BHT/g powder for DRSC, 5.42 mg BHT/g powder for HORAC, and 8.89 mg BHT/g powder for ORAC. Composition and AA assays of individual polyphenols from the EAE were then performed. Phloridzin and phloretin accounted for 46.70 and 41.94 % of TFD, respectively. Phloretin displayed the highest AA, followed by phloridzin. Finally, the antimicrobial activities of the EAE, phloridzin, and phloretin were evaluated. EAE displayed good inhibitory activities against Staphylococcus aureus with a minimum inhibition concentration (MIC) of 1.25 mg/ml and against Escherichia coli with a MIC of 2.50 mg/ml. Phloridzin and phloretin showed better inhibitory activities than the EAE, which were MICs of 0.50 and 0.10 mg/ml, respectively, against S. aureus and MICs of 1.50 and 0.75 mg/ml, respectively, against E. coli.ConclusionsEthyl acetate was the best solvent of choice to extract natural products to obtain the maximum antioxidant and antibacterial benefits. Phloridzin and phloretin have the potential to be used as natural alternatives to synthetic antioxidants and antimicrobials.
Background Growing evidence supports a link between ultra-processed food consumption and human health outcomes. However, the association between ultra-processed food consumption and non-alcoholic fatty liver disease (NAFLD) is not known. We aimed to explore the association between ultra-processed food consumption and risk of NAFLD. Methods The prospective study included 16 168 participants aged 18–90 years from the Tianjin Chronic Low-grade Systemic Inflammation and Health (TCLSIH) Cohort Study. Information on ultra-processed food consumption was collected at baseline using a validated food frequency questionnaire. NAFLD was defined as the presence of sonographic fatty liver in the absence of significant alcohol intake (≥210 g/week for men and ≥140 g/week for women, respectively) and other liver diseases. Multivariable Cox proportional hazards models were used to examine the association between ultra-processed food consumption and risk of NAFLD. Results During 56 935 person-years of follow-up, we documented 3752 incident NAFLD cases. After adjusting for age, sex, body mass index, smoking, alcohol drinking, education, occupation, income, physical activity, total energy intake, personal and family history of disease and overall diet quality, the multivariable hazard ratios (95% confidence interval) of NAFLD across increasing quartiles of ultra-processed food consumption were 1.00 (reference), 0.99 (0.90, 1.08), 1.13 (1.03, 1.25) and 1.18 (1.07, 1.30), respectively (P for trend <0.0001). The hazard ratio (95% confidence interval) per one standard deviation increase in ultra-processed food consumption, equivalent to a 62.7 g/1000 kcal per day, was 1.06 (1.03, 1.09), P = 0.0001. Conclusions Our study indicates that higher ultra-processed food consumption is associated with a higher risk of NAFLD. This finding suggests that ultra-processed food, which is widely consumed worldwide, might be a modifiable dietary target to reduce the risk of NAFLD.
Selenium (Se) is an essential trace element for human health and animal nutrition. The aim of this study was to evaluate the inhibitory activities of Se-enriched lactic acid bacteria (LAB), Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus, against pathogenic Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes in vitro. The results indicated that the accumulation amount of Se by Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus reached 12.05 ± 0.43 µg/mL and 11.56 ± 0.25 µg/mL, respectively, accompanied by the relative maximum living cells when sodium selenite was 80 µg/mL. Oxford cup double plate assay showed that bacterial culture solution and cell-free culture supernatant (CFCS) from Se-enriched LAB exerted stronger antibacterial activity than those from the non-Se strains. The growth of pathogenic bacterial culture with CFCS at any growth stages was worse than that without CFCS; moreover, the inhibiting effect of CFCS of Se-enriched LAB was more significant than that of non-Se strains. Results from a scanning electron microscope equipped with energy dispersion X-ray spectrometry showed that elemental Se nanoparticles, which characteristically energy peak around 1.42 keV, were deposited on the cell surfaces of Lactobacillus delbrueckii ssp. bulgaricus. In addition, CFCS of Se-enriched LAB induced more serious cell structure damage of pathogenic bacteria than did non-Se LAB.
Background Epidemiological evidence for the association of soft drink consumption with nonalcoholic fatty liver disease (NAFLD) is inconsistent, and such association has not been prospectively examined in the general adult population. Objectives We aimed to investigate the prospective association between soft drink consumption and the risk of NAFLD in a Chinese adult population. Methods This prospective cohort study investigated 14,845 participants [mean age: 39.3 y; 6203 (41.8%) men] who were free of liver disease, cardiovascular disease, and cancer at baseline. Soft drink consumption (mainly sugar-containing carbonated beverages) was measured at baseline using a validated FFQ. NAFLD was diagnosed based on abdominal ultrasound without significant alcohol consumption and other causes of liver disease. Hepatic steatosis index (HSI) was calculated based on sex, BMI, and blood transaminase levels. Cox proportional hazards regression models were used to examine the association of soft drink consumption with incident NAFLD. Results A total of 2888 first-incident cases of NAFLD occurred during 42,048 person-years of follow-up (median follow-up: 4.2 y). After adjusting for demographic characteristics, lifestyle factors, dietary intake, and inflammatory markers, the multivariable HRs (95% CIs) for incident NAFLD were 1.00 (reference) for <1 serving/wk, 1.18 (1.03, 1.34) for 1 serving/wk, 1.23 (1.08, 1.40) for 2–3 servings/wk, and 1.47 (1.25, 1.73) for ≥4 servings/wk, respectively (P for trend < 0.0001). Further sensitivity analysis showed that the corresponding multivariable HRs (95% CIs) for incident HSI-defined NAFLD were 1.00 (reference), 0.96 (0.70, 1.31), 1.16 (0.83, 1.62), and 1.59 (1.07, 2.37), respectively (P for trend < 0.0001). Conclusions The results from our prospective study indicate that soft drink consumption is associated with an increased risk of NAFLD in Chinese adults. This study was registered at UMIN Clinical Trials Registry as UMIN000027174.
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