New dipeptidyl peptidase IV (DPP-IV)-inhibitory peptides from trypsin/chymotrypsin-treated goat milk casein hydrolysates were isolated and identified by two-dimensional silica thin-layer chromatography (2D-TLC) combined to nano LC-MS/MS. 2D-TLC with chloroform/methanol/25% ammonia (2:2:1) and n-butanol/acetic acid/water (4:1:1) as the first- and second-dimension eluents, respectively, in analytical and semipreparative scales, was set up and verified by reversed-phase high-performance liquid chromatography (RP-HPLC) to be feasible and efficient to separate the hydrolysates. Five new DPP-IV-inhibitory peptides, four relatively large oligopeptides (MHQPPQPL, SPTVMFPPQSVL, VMFPPQSVL, and INNQFLPYPY), and AWPQYL were identified, and INNQFLPYPY showed a notable IC50 value of 40.08 μM as an uncompetitive inhibitor. Interactive effects on DPP-IV inhibition were also observed among separated fractions and pure synthetic peptide mixtures with concentration-dependent activity. The study gives new insights into goat casein hydrolysates with identified DPP-IV-inhibitory peptides efficiently isolated by 2D-TLC, which provides a simple and cost-efficient separation process and is compatible with liquid chromatography-tandem mass spectrometry (LC-MS/MS) identification.

PurposeThe purpose of this paper is to investigate the purchasing behaviours of two Beijing wine consumer groups and evaluate the influence of different factors on their decision making process to provide information to better understand the Chinese wine market and assist with market entry and penetration.Design/methodology/approachA questionnaire with 27 single choice or scoring questions and a set of 13 best–worst (BW) scaling questions is designed. Typical consumers in supermarkets and university students are invited to answer the questionnaire which uses a mix of nominal and rating scale responses as well as a BW choice experiment.FindingsThe results show that the consumers intend to pay low prices for daily use wines, but high prices for wines for gift purposes. Domestic brands constituted the highest proportion of the purchases, followed by French wines. The consumers are sensitive on price and country of wine origin; awards, medals, and vintage were of low influences in wine purchasing decisions. Typical consumers like supermarkets and boutique wine shops, while university students prefer the internet for on‐line sales. In the BW experiment, tasting the wine previously, the origin of the wine and brand name listed are the most influential factors in purchasing decisions.Originality/valueThe overall picture of wine preference of Beijing consumers is reported for the first time. It provides an understanding of the factors in wine purchasing decision making and their relative importance. The result could better facilitate wine promotion and penetration in this promising and unique market.

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The dipeptidyl peptidase IV (DPP-IV)-inhibitory bioactivity of silver carp protein (SCP) hydrolysates were investigated, and their containing efficacious DPP-IV-inhibitory peptides were explored by in silico hydrolysis analysis, peptide separation combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) identification, and chemical synthesis. SCP hydrolysates generated by six proteases all showed efficient DPP-IV-inhibitory activities, and Neutrase-generated hydrolysates had the greatest DPP-IV inhibition (IC50 of 1.12 mg/mL). In silico Neutrase hydrolysis revealed hundreds of fragments released from myosin, actin, and collagen of SCPs, which include different Pro-motif peptides but only three reported peptidic DPP-IV inhibitors with moderate or weak bioactivity. In addition, three new DPP-IV-inhibitory peptides were identified using LC-MS/MS; in particular, LPIIDI and APGPAGP showed high DPP-IV-inhibitory activity with IC50 of 105.44 and 229.14 μM, respectively, and behaved in competitive/non-competitive mixed-type DPP-IV inhibition mode. The results indicate that the SCP-derived DPP-IV-inhibitory peptides could be potential functional ingredients in the diabetic diet.

Intestinal bifidobacteria benefit human health by promoting and modulating the gut flora, and boosting therapeutic efficiency for chronic metabolic diseases and cancer. Recently, Bifidobacterium adolescentis strains with high adhesion to intestinal epithelial cells were associated with induction of T-helper 17 (Th17) cells in humans and rodents. Here, two B. adolescentis strains with similar adhesive ability but different aggregation properties were investigated for specific immunoregulatory effects, including the underlying cellular pathway, on macrophage and T-regulatory (Treg)/Th17 axis activation in vitro and in the colon of dextran sodium sulfate (DSS)-colitis mice in vivo. In-vitro, the auto-aggregative B. adolescentis strain IF1-11 induced significantly higher IL-6 and lower IL-10 secretion from immune cells, and it induced abundant Th17 cells. The non-aggregating strain IF1-03 induced significantly higher IL-10, less IL-6 and a high proportion of Treg/Th17 cells compared to total T cells. In vivo, orally administered IF1-03 protected DSS-colitis mice via activation of dendritic cells or macrophages and skewing of Treg/Th17 cells, consistent with Treg cell induction in vitro. IF1-03 exopolysaccharides showed a functional recognition pattern similar to IF1-03 for IL-10 cytokine secretion and Treg cell-differentiation induction, both dependent on the toll-like receptor 2–ERK/p38 MAPK-signaling cascade for macrophage activation. We suggest that B. adolescentis exopolysaccharide-associated enterocyte adhesion/aggregation phenotypes determine strain-specific adaptive immune responses in the gut via the macrophage-regulated Treg/Th17 axis.

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Experience products are those the quality of which cannot be ascertained until after consumption, forcing consumers to base their purchase decision on an expectation of the product's quality. This expected quality is based on cues available before purchase, among which price is noteworthy, as consumers tend to believe that higher prices imply higher quality. But price also stresses the consumers' budget restriction, inducing a double-and conflicting-global effect on purchase probability. Using the traditional formulation of Random Utility Models for experience goods (i.e. introducing all attributes directly in the utility function) can lead to an endogeneity problem due to the omission of expected quality, introducing bias on the results. Using a stated wine choice experiment conducted in China as a case study, we correct for endogeneity by modelling each alternative's expected quality as a latent variable, explained by all available quality cues, including price. Then we explain choice as a tradeoff between price and expected quality. This allows us to separate both effects of price and correct for at least one source of endogeneity while being consistent with behavioural theory; this has either been ignored or not treated correctly in previous literature. Moreover, as the model requires only a quality indicator for each alternative to achieve identification, the respondents' burden increases marginally. Our results show that the use of latent variables reduces endogeneity and effectively allows to measure both effects of price separately, obtaining higher significance and correct signs for its parameters.

BackgroundProteinaceous bioactive substances and pharmaceuticals are most conveniently administered orally. However, the facing problems are the side effects of proteolytic degradation and denaturation in the gastrointestinal tract. In recent years, lactic acid bacteria (LAB) have been verified to be a promising delivery vector for susceptible functional proteins and drugs. KiSS-1 peptide, a cancer suppressor, plays a critical role in inhibiting cancer metastasis and its activity has been confirmed by direct administration. However, whether this peptide can be functionally expressed in LAB and exert activity on cancer cells, thus providing a potential alternative administration manner in the future, has not been demonstrated.ResultsA recombinant Lactococcus lactis strain NZ9000-401-kiss1 harboring a plasmid containing the gene of the tumor metastasis-inhibiting peptide KiSS1 was constructed. After optimization of the nisin induction conditions, the recombinant strain efficiently secreted KiSS1 with a maximum detectable amount of 27.9 μg/ml in Dulbecco’s Modified Eagle medium. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide and would healing assays, respectively, indicated that the secreted KiSS1 peptide remarkably inhibited HT-29 cell proliferation and migration. Furthermore, the expressed KiSS1 was shown to induce HT-29 cell morphological changes, apoptosis and reduce the expression of matrix metalloproteinase 9 (MMP-9) at both mRNA and protein levels.ConclusionsA recombinant L. lactis NZ9000-401-kiss1 successfully expressing the human kiss1 was constructed. The secreted KiSS1 peptide inhibited human HT-29 cells’ proliferation and migration probably by invoking, or mediating the cell-apoptosis pathway and by down regulating MMP-9 expression, respectively. Our results suggest that L. lactis is an ideal cell factory for secretory expression of tumor metastasis-inhibiting peptide KiSS1, and the KiSS1-producing L. lactis strain may serve as a new tool for cancer therapy in the future.