Comparative effects of vacuum or conventional frying on the polyphenol chemistry and in vitro colon cancer stem cell inhibitory activity of purple-flesh potatoes.

Potatoes are an important food crop that undergo postharvest storage, reconditioning, and cooking. Colored-flesh varieties of potatoes are rich in phenolic acids and anthocyanins. Previous studies have suggested that purple-flesh potatoes can inhibit colon cancer cells in vitro and reduce colon carcinogenesis in vivo. Vacuum frying (VF), as an alternative to conventional frying (CF), reduces fat content and may promote polyphenol retention in potato chips. We examined the impacts of reconditioning (storing at 13°C for 3 weeks following the 90-day cold storage at 7°C) and frying method on phenolic chemistry and in vitro colon cancer stem cell (CCSC) inhibitory activity of purple-flesh potato chips. We found that reconditioned chips exhibited higher total phenolic content (TPC) than nonreconditioned chips. We found that VF chips had lower TPC than CF chips. We observed no interaction between treatments. We found that VF chips had 27% higher total monomeric anthocyanin levels than CF chips, and observed a significant interaction between treatments. We found that VF chips had higher concentrations of caffeic acid (42%-72% higher), malvidin (46%-98% higher), and pelargonidin (55%-300% higher) than CF chips. We found that reconditioning had no effect. We found that VF chips had greater in vitro CCSC inhibitory activity than CF chips. Our results suggest that VF can improve the phytochemical profile and health-related functionality of purple-flesh potato chips, but additional studies are needed to determine if these results translate to the in vivo situation. PRACTICAL APPLICATION: Our current study shows that vacuum frying of purple-flesh potato chips results in higher levels of total monomeric anthocyanins and concentrations of specific polyphenols as compared to chips produced by conventional frying. These differences correlated with better in vitro colon cancer stem cell inhibitory activity. Although additional in vivo studies are needed, our current results suggest that it may be possible for potato processors to improve the health-related functionality of purple-flesh potato chips through the use of vacuum frying.

Impact of copper-based fungicides on the antioxidant quality of ethanolic hop extracts.

Hops contain a variety of compounds possessing antioxidant capacity including phenolic and polyphenolic compounds as well as α- and ß- acids. These compounds may contribute to the oxidative stability of beer during brewing and storage. Hop plants may be treated with copper-based fungicides (CBFs) which have been shown to increase the total copper content of harvested hop cones; however, copper ions are well known to catalyze the generation of reactive oxygen species production in beer and may negatively impact its oxidative stability. Increased copper content in CBF-treated hops has been previously shown to have deleterious effects on the aroma quality of hops and beer. The impact of CBFs on the antioxidant content and quality of hops has not been previously investigated. In this study, ethanolic extracts of CBF-treated hops are evaluated for their metal content and antioxidant quality in order to determine whether excess copper from CBF treatment negatively impacts their antioxidant capacity.

Mitigation of nonalcoholic fatty liver disease in high-fat-fed mice by the combination of decaffeinated green tea extract and voluntary exercise.

We have shown that combination treatment with decaffeinated green tea extract (GTE) and voluntary exercise (Ex) reduces obesity and insulin resistance in high-fat (HF)-fed mice to a greater extent than either treatment alone. Here, we investigated the effects of GTE-, Ex- or the combination on the development of obesity-related NAFLD. Male C57BL/6 J mice were treated for 16 weeks with HF diet (60% energy from fat), HF supplemented with 7.7 g GTE/kg, HF plus access to a voluntary running wheel, or the combination. We found that treatment of mice with the combination mitigated the development of HF-induced NAFLD to a greater extent than either treatment alone. Combination-treated mice had lower plasma alanine aminotransferase (92% lower) and hepatic lipid accumulation (80% lower) than HF-fed controls: the effect of the single treatments was less significant. Mitigation of NAFLD was associated with higher fecal lipid and nitrogen levels. Combination treated, but not singly treated mice, had higher hepatic expression of genes related to mitochondrial biogenesis (sirtuin 1 [59%]; peroxisome proliferator-activated receptor γ coactivator 1α [42%]; nuclear respiratory factor 1 [38%]; and transcription factor B1, mitochondrial [89%]) compared to the HF-fed controls. GTE-, Ex-, and the combination-treatment groups also had higher hepatic expression of genes related to cholesterol synthesis and uptake, but the combination was not better than the single treatments. Our results suggest the combination of GTE and Ex can effectively mitigate NAFLD. Future studies should determine if the combination is additive or synergistic compared to the single treatments.

Soy protein concentrate mitigates markers of colonic inflammation and loss of gut barrier function in vitro and in vivo.

Whereas a number of studies have examined the effects of soy isoflavones and tocopherols on colonic inflammation, few have examined soy protein. We determined the radical scavenging and cytoprotective effects of soy protein concentrate (SPC) in vitro and its anti-inflammatory effects in dextran sulfate sodium (DSS)-treated mice. Cotreatment with SPC protected Caco-2 human colon cells from H2O2-induced cell death and mitigated intracellular oxidative stress. Treatment of differentiated Caco-2 cells with SPC blunted DSS-induced increases in monolayer permeability. Pepsin/pancreatin-digested SPC had reduced radical scavenging activity, but retained the monolayer protective effects of SPC. In vivo, 1.5% DSS caused body weight loss, colon shortening, and splenomegaly in CF-1 mice. Co-treatment with 12% SPC mitigated DSS-induced body weight loss and splenomegaly. DSS increased colonic interleukin (IL)-1ß, IL-6, and monocyte chemotactic protein-1 expression. The levels of these markers were significantly lower in mice co-treated with SPC. SPC prevented DSS-mediated reductions in colonic glucagon-like peptide 2 levels, suggesting that SPC can prevent loss of gut barrier function, but no significant effect on claudin 1 and occludin mRNA levels of was observed. SPC-treated mice had lower colonic mRNA expression of toll-like receptor 4 and nucleotide-binding oligomerization domain-containing protein-like receptor family, pyrin domain containing protein 3 (NLRP3), and lower caspase-1 enzyme activity than DSS-treated mice. In summary, SPC exerted antioxidant and cytoprotective effects in vitro and moderated the severity of DSS-induced inflammation and loss of gut barrier function in vivo. These effects appear to be mediated in part through reduced NLRP3 expression and caspase 1 activity.