Improved Extraction and Sample Cleanup of Tri-glycoalkaloids α-Solanine and α-Chaconine in Non-denatured Potato Protein Isolates

Glycoalkaloids in potato-derived products result in bitter taste and potentially toxic effects at high intakes. Generally, extraction of glycoalkaloids prior to HPLC analysis is carried out by dilute acetic acid. For most potato-derived extracts including heat-coagulated potato proteins, this extraction method is sufficient to achieve satisfying tri-glycoalkaloid (TGA) recoveries. Soluble potato proteins obtained by non-denaturing processes show different requirements for glycoalkaloid extraction. TGA extraction was optimized for two commercially available native potato protein isolates and compared to heat-coagulated potato protein. The highest TGA levels were determined in the extract when extraction was carried out at 40 °C by at least 5 % acetic or propionic acid supplemented with 20 mM Na-1-heptanesulfonate (HSA). Addition of HSA results in substantially improved TGA extraction and induces precipitation of soluble protein which enhanced sample cleanup. On the contrary, extraction of TGA from coagulated potato protein in the presence of HSA showed a reduced TGA extraction efficiency. This improved TGA extraction procedure for soluble non-denatured potato protein isolates results in reliable quantification of bitter tasting and toxic glycoalkaloid levels. This contributes to a non-bitter and safe use of the nutritional and functional benefits of this plant protein in food applications.     

Using sequence variants of a QTL region improves the accuracy of genomic evaluation in French Saanen goats

The enhanced availability of sequence data in livestock provides an opportunity for more accurate predictions in routine genomic evaluations. Such evaluations would therefore no longer rely only on the linkage disequilibrium between a chip marker and the causal mutation. The objective of this study was to assess the usefulness of sequence data in Saanen goats (n = 33) to better capture a quantitative trait locus (QTL) on chromosome 19 (CHI19) and improve the accuracy of predictions for 3 milk production traits, 5 type traits, and somatic cell scores. All 1,207 50K genotypes were imputed to the sequence level. Four scenarios, each using a subset of CHI19 imputed variants, were then tested. Sequence-derived information included all CHI19 variants (529,576), all variants in the QTL region (22,269), 178 variants selected in the QTL region and added to an updated chip, or 178 randomly selected variants on CHI19. Two genomic evaluation models were applied: single-step genomic BLUP and weighted single-step genomic BLUP. All scenarios were compared with single-step genomic BLUP using 50K genotypes. Best overall results were obtained using single-step genomic BLUP on 50K genotypes completed with all variants in the QTL region of chromosome 19 (6.2% average increase in accuracy for 9 traits) with the highest accuracy gain for fat yield (17.9%), significant increases for milk (13.7%) and protein yields (12.5%), and type traits associated with CHI19. Despite its association with the QTL region of chromosome 19, the somatic cell score showed decreased accuracy in every alternative scenario. Using all CHI19 variants led to an overall decrease of 4.8% in prediction accuracy. The updated chip was efficient and improved genomic evaluations by 3.1 to 6.4% on average, depending on the scenario. Indeed, information from only a few carefully selected variants increased accuracies for traits of interest when used in a single-step genomic BLUP model. In conclusion, using QTL region variants imputed from sequence data in single-step genomic evaluations represents a promising perspective for such evaluations in dairy goats. Furthermore, using only a limited number of selected variants in QTL regions, as available on SNP chip updates, significantly increases the accuracy for QTL-associated traits without deteriorating the evaluation accuracy for other traits. The latter approach is interesting, as it avoids time-consuming imputation and data formatting processes and provides reliable genotypes.     

Mycotoxin exposure and human cancer risk: A systematic review of epidemiological studies

In recent years, there has been an increasing interest in investigating the carcinogenicity of mycotoxins in humans. This systematic review aims to provide an overview of data linking exposure to different mycotoxins with human cancer risk. Publications (2019 and earlier) of case–control or longitudinal cohort studies were identified in PubMed and EMBASE. These articles were then screened by independent reviewers and their quality was assessed according to the Newcastle–Ottawa scale. Animal, cross‐sectional, and molecular studies satisfied criteria for exclusion. In total, 14 articles were included: 13 case–control studies and 1 longitudinal cohort study. Included articles focused on associations of mycotoxin exposure with primary liver, breast, and cervical cancer. Overall, a positive association between the consumption of aflatoxin‐contaminated foods and primary liver cancer risk was verified. Two case–control studies in Africa investigated the relationship between zearalenone and its metabolites and breast cancer risk, though conflicting results were reported. Two case–control studies investigated the association between hepatocellular carcinoma and fumonisin B1 exposure, but no significant associations were observed. This systematic review incorporates several clear observations of dose‐dependent associations between aflatoxins and liver cancer risk, in keeping with IARC Monograph conclusions. Only few human epidemiological studies investigated the associations between mycotoxin exposures and cancer risk. To close this gap, more in‐depth research is needed to unravel evidence for other common mycotoxins, such as deoxynivalenol and ochratoxin A. The link between mycotoxin exposures and cancer risk has mainly been established in experimental studies, and needs to be confirmed in human epidemiological studies to support the evidence‐based public health strategies.     

SYBR®Green qPCR screening methods for the presence of “35S promoter” and “NOS terminator” elements in food and feed products

The Cauliflower Mosaic Virus “35S promotor” (p35S) and the Agrobacterium “Nopaline Synthase” terminator (tNOS) are the most represented generic recombinant elements in commercial genetically modified crops to date. A set of four new SYBR^®Green qPCR methods targeting the “p35S” and “tNOS” core elements have been developed. These qPCR methods generate short amplicons of 147 and 75 bp for the “p35S” element and 172 and 69 bp for the “tNOS” element. Single target plasmids containing these amplicons were constructed and allow determining the nominal melting temperature (T _m value) of each amplicon. The four methods are specific for their respective targets, and moreover, three of them are highly sensitive (up to 1–2 copies detectable) at a PCR efficiency ranging between 95 and 100%. The latter methods can detect their respective targets at 0.1% (w/w) gDNA levels and are suitable for detecting low levels of genetically modified materials containing the “p35S” and/or “tNOS” elements.     

A method for characterising cook loss and water holding capacity in heat treated cod (Gadus morhua) muscle

The currently available methods for measuring water holding capacity (WHC) have been developed for raw material characterisation and have been applied to processed (cooked) muscle samples. The intrinsic shortcoming of the methods is that they do not allow rapid and uniform heating, which make them unsuitable for investigating the kinetics of cook loss and WHC. A new method and associated equipment (sample cups) for rapid and uniform heating that allows studying cook loss, water holding capacity and texture of fish samples was developed. After heating and cooling of samples in the sample cup it is feasible to gravimetrically determine the cook loss with a standard deviation within 30% of the total cook loss for minced samples. Both intact and coarsely minced muscle of farmed cod was used to investigate the abilities and limitations of the method with respect to WHC.     

Effect of starvation on the performance and re-acclimation of biotrickling filters for air pollution control

Biotrickling filters for air pollution control are expected to encounter fluctuating conditions or periods without pollutant supply. In the present study, we investigated the effect of pollutant starvation in bench-scale biotrickling filters treating toluene. The experimental protocol consisted of starving biotrickling filters under various conditions: with or without airflow, with or without liquid recycle, and with or without an alternate carbon source (glucose) supply. The duration of the period without toluene was varied from 2 to 9 days, during time which the biotrickling filters were monitored for biomass content, endogenous and toluene-induced oxygen uptake rates during starvation, and toluene overall elimination capacity after restart. During starvation, all reactors lost their ability to degrade toluene within 5 days, regardless of the mode of starvation. The biomass content significantly decreased during starvation, in particular in those reactors where the recycle liquid was maintained, but this decrease was not critical for future re-acclimation. Glucose addition to starved biotrickling filters had several detrimental effects. It resulted in a faster decrease of the biomass content and slowed the reacclimation phase. Overall, the results show that the reacclimation of toluene-degrading biotrickling filters after periods of nonuse is short (10-24 h to re-establish full performance), and they suggest that, in the case of toluene-degrading biotrickling filters, re-acclimation time is largely governed by the induction of key pollutant-degrading enzymes.     

Seasonal vitamin D intake in Quebec preschoolers.

As a number of seasonal factors affect cutaneous synthesis of vitamin D, especially in young children, our objective was to verify if winter and summer vitamin D intakes in Quebec preschoolers reach the adequate intake of 5 microg/day. A three-month retrospective food frequency questionnaire and a 24-hour food recall were used with parents of 98 children (mean age 56 months) in summer and of 72 of these children (mean age 65 months) in winter. To ensure completeness of data, vitamin D content of foods not covered in the Canadian Nutrient File was taken from other sources. According to the food frequency questionnaire, total vitamin D intakes were 9.7 +/- 4.3 microg/day in summer and 11.6 +/- 4.8 microg/day in winter. Only 10% of children in summer and 7% in winter had an intake below 5 microg/day. The 24-hour food recall vitamin D intake estimate was lower (summer 7.0 +/- 3.8 microg/day, winter 7.2 +/- 4.2 microg/day). This difference could be partly due to a discrepancy in the estimation of multivitamin supplement intake. However, according to both estimates, vitamin D intakes appeared generally adequate in this sample of Quebec preschoolers.     

In vitro β‐Carotene Bioaccessibility and Lipid Digestion in Emulsions: Influence of Pectin Type and Degree of Methyl‐Esterification

Citrus pectin (CP) and sugar beet pectin (SBP) were demethoxylated and fully characterized in terms of pectin properties in order to investigate the influence of the pectin degree of methyl‐esterification (DM) and the pectin type on the in vitro β‐carotene bioaccessibility and lipid digestion in emulsions. For the CP based emulsions containing β‐carotene enriched oil, water and pectin, the β‐carotene bioaccessibility, and lipid digestion were higher in the emulsions with pectin with a higher DM (57%; “CP57 emulsion”) compared to the emulsions with pectin with a lower DM (30%; “CP30 emulsion”) showing that the DM plays an important role. In contrast, in SBP‐based emulsions, nor β‐carotene bioaccessibility nor lipid digestion were dependent on pectin DM. Probably here, other pectin properties are more important factors. It was observed that β‐carotene bioaccessibility and lipid digestion were lower in the CP30 emulsion in comparison with the CP57, SBP32, and SBP58 emulsions. However, the β‐carotene bioaccessibility of CP57 emulsion was similar to that of the SBP emulsions, whereas the lipid digestion was not. It seems that pectin type and pectin DM (in case of CP) are determining which components can be incorporated into micelles. Because carotenoids and lipids have different structures and polarities, their incorporation may be different. This knowledge can be used to engineer targeted (digestive) functionalities in food products. If both high β‐carotene bioaccessibility and high lipid digestion are targeted, SBP emulsions are the best options. The CP57 emulsion can be chosen if high β‐carotene bioaccessibility but lower lipid digestion is desired.     

Survival of Lactobacillus rhamnosus strains in the upper gastrointestinal tract

In the present study six probiotic Lactobacillus rhamnosus strains were investigated for their ability to survive in the human upper gastrointestinal tract through a dynamic gastric model of digestion. MRS broth was used as delivery vehicle and survival was investigated during in vitro gastric and gastric plus duodenal digestion. Results highlighted that all tested strains showed good survival rate during both gastric and duodenal digestion. In particular, three strains exhibited a great survival showing a recovery percentage in the range between 117 and 276%. In agreement with survival data, high lactic acid production was detected for all strains, confirming their metabolic activity during digestion.