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Andrea Rivera del Rio, Mauricio Opazo-Navarrete, Yamira Cepero-Betancourt, Gipsy Tabilo-Munizaga, Remko M. Boom, Anja E.M. Janssen. Heat-induced changes in microstructure of spray-dried plant protein isolates and its implications on in vitro gastric digestion

DOI: https://doi.org/10.1016/j.lwt.2019.108795

Link: https://www.sciencedirect.com/science/article/pii/S0023643819311375

Resumen

he quickly expanding field of plant-based food, generally uses protein concentrates or isolates as protein source. It is however not clear to what extent the intensive processing of these raw materials affects their digestibility. We here report on the in vitro gastric digestibility of the structures present in unheated and heated dispersions of spray-dried protein isolates of soybean and yellow pea. Unheated dispersions consist primarily of insoluble individual spray-dried particles, agglomerates of these and only a small fraction of soluble protein. Pepsin activity was followed in real-time through microscopic observations, showing the disassociation of agglomerates and inward-breakdown of individual particles, which are otherwise stable at gastric pH and ionic strength. This demonstrates that solubility is not necessarily an incentive for gastric protein digestion.

Heating does not significantly affect the overall digestibility of protein isolate dispersions. Nevertheless, heating disrupts the structure of spray-dried particles, increasing the amount of smaller and better digestible particles that remain suspended after centrifugation. Conversely, heat-induced aggregates remain in the pellet and are up to 50% less digestible than their unheated counterparts. This impaired digestibility is counterbalanced by a reduced proportion of poorly-digestible species in the full system (up to 11% for soy and 23% for pea).

Keywords: flax; genome-wide association study (GWAS); selective sweep; genotyping by sequencing (GBS); bi-parental population; single nucleotide polymorphism (SNP); seed yield; plant height; maturity; fatty acid composition

You F., Xiao J., Li P., Yao Z., Jia G., He L., Kumar S., Soto-Cerda B., Duguid S., Booker H., Rashid K., Cloutier S. (2018) Genome-Wide Association Study and Selection Signatures Detect Genomic Regions Associated with Seed Yield and Oil Quality in Flax. International Journal of Molecular Sciences19:2303.

DOI: https://doi.org/10.3390/ijms19082303

Link: https://www.mdpi.com/1422-0067/19/8/2303

Resumen

A genome-wide association study (GWAS) was performed on a set of 260 lines which belong to three different bi-parental flax mapping populations. These lines were sequenced to an averaged genome coverage of 19× using the Illumina Hi-Seq platform. Phenotypic data for 11 seed yield and oil quality traits were collected in eight year/location environments. A total of 17,288 single nucleotide polymorphisms were identified, which explained more than 80% of the phenotypic variation for days to maturity (DTM), iodine value (IOD), palmitic (PAL), stearic, linoleic (LIO) and linolenic (LIN) acid contents. Twenty-three unique genomic regions associated with 33 quantitative trait loci (QTL) for the studied traits were detected, thereby validating four genomic regions previously identified. The 33 QTL explained 48–73% of the phenotypic variation for oil content, IOD, PAL, LIO and LIN but only 8–14% for plant height, DTM and seed yield. A genome-wide selective sweep scan for selection signatures detected 114 genomic regions that accounted for 7.82% of the flax pseudomolecule and overlapped with the 11 GWAS-detected genomic regions associated with 18 QTL for 11 traits. The results demonstrate the utility of GWAS combined with selection signatures for dissection of the genetic structure of traits and for pinpointing genomic regions for breeding improvement. View Full-Text

Keywords: flax; genome-wide association study (GWAS); selective sweep; genotyping by sequencing (GBS); bi-parental population; single nucleotide polymorphism (SNP); seed yield; plant height; maturity; fatty acid composition

Osorio C. (2019) The Role of Orange Gene in Carotenoid Accumulation: Manipulating Chromoplasts Toward a Colored Future. Frontiers in Plant Science, 10:1235.

DOI: https://doi.org/10.3389/fpls.2019.01235

Link: https://www.frontiersin.org/articles/10.3389/fpls.2019.01235/full

Resumen

Carotenoids are isoprenoid pigments synthesized in plants, algae, and photosynthetic bacteria and fungus. Their role is essential in light capture, photoprotection, pollinator attraction, and phytohormone production. Furthermore, they can regulate plant development when they are processed as small signaling molecules. Due to their importance for human health, as promoters of the immune system and antioxidant activity, carotenoids have been used in the pharmaceutical, food, and nutraceutical industries. Regulation of carotenoid synthesis and accumulation has been extensively studied. Excellent work has been done unraveling the mode of action of phytoene synthase (PSY), a rate-limiting enzyme of carotenoid biosynthesis pathway, in model species and staple crops. Lately, interest has been turned to Orange protein and its interaction with PSY during carotenoid biosynthesis. Discovered as a dominant mutation in Brassica oleracea, Orange protein regulates carotenoid accumulation by posttranscriptionally regulating PSY, promoting the formation of carotenoid-sequestering structures, and also preventing carotenoid degradation. Furthermore, Orange protein contributes to homeostasis regulation, improving plant tolerance to abiotic stress. In this mini review, the focus is made on recent evidence that elucidates Orange protein mode of action and expression in different plant species. Additionally, strategies are proposed to modify Orange gene by utilization of genome editing techniques. A better understanding of carotenoid biosynthesis and accumulation will lead to a positive impact on the development of healthy food for a growing population.

Bustamante M., Oomah D., Mosi-Roa Y., Rubilar M., Burgos-Díaz C. (2019) Probiotics as an Adjunct Therapy for the Treatment of Halitosis, Dental Caries and Periodontitis. Probiotics & Antimicrobial Proteins

DOI: https://doi.org/10.1007/s12602-019-9521-4

Link: https://link.springer.com/article/10.1007/s12602-019-9521-4

Resumen

Probiotics and prebiotics are popular among consumers worldwide as natural approaches to prevent gastrointestinal diseases. The effects of their consumption on the gastrointestinal system have been extensively investigated. Recently, the efficacy of probiotics and prebiotics has been evaluated against naturally developing microbiome imbalance in the human body, such as in the oral cavity, skin, female urogenital tract, and respiratory tract. This review examines the scientific data related to the effects of probiotics on the treatment of diseases occurring in the oral cavity. Probiotics can effectively prevent and treat some infectious diseases in the oral cavity, such as halitosis and periodontitis, and can reduce the development of dental caries and the concentration of harmful bacteria, according to clinical studies. The results of this meta-analysis also suggest the use of probiotics to treat halitosis and periodontitis. However, the evidence may be inconclusive due in part to the use of a wide range of probiotics, non-standardized study design, small population size, poor quality reports, and inconsistent data. Therefore, future studies should homogenize terms and definitions for primary and secondary outcomes, increase the number of volunteers/patients in in vitro tests and clinical studies, and include an evaluation of the combined use of pre- and probiotics.

Soto-Cerda B., Cloutier S., Gajardo H., Aravena G., Quian R. (2019) Identifying drought-resilient flax genotypes and related-candidate genes based on stress indices, root traits and selective sweep. Euphytica. 215: 41.

DOi: https://doi.org/10.1007/s10681-019-2362-0

Link: https://link.springer.com/article/10.1007/s10681-019-2362-0

Resumen

Drought hampers flax yield and oil quality particularly at the reproductive stage. Here, 105 flax accessions were assessed for drought tolerance under irrigated and drought-stressed conditions across three environments using eight stress indices. Total root length (TRL), total root volume (TRV) and diameter class length (DCL) were analyzed in two selected groups of accessions contrasting for drought tolerance. These genotypes were further submitted to selective sweep analysis using 394 genome-wide microsatellite (SSR) loci to identify markers potentially associated with drought tolerance and drought-responsive candidate genes. The results obtained for yield under stress (Ys) and yield under irrigated condition (Yp) indicated significant genotypic response to water treatments (P < 0.001). Hierarchical clustering and heatmap analyses of stress indices identified the oil type flax cultivars O_CAN_C_CN19004 (AC Emerson) and O_CAN_C_CN19003 (AC McDuff) as the most drought tolerant. Some fiber type flax accessions were also clustered in the tolerant group. The drought tolerant group showed 29, 42, and 22% superior TRL, TRV and DCL, respectively, than its sensitive counterpart under drought. The SSR loci under selective sweep, Lu254 and Lu709 were significantly associated with Ys, and accessions carrying the favorable haplotype exhibited 21.7% higher Ys. Various candidate genes involved in absicic acid pathway, auxin signaling, Ca2+ signaling, photosynthesis regulation, and drought-responsive transcription factors were identified at the selective sweep loci. The identified tolerant accessions can be used for conferring drought tolerance to elite cultivars, while the selective sweep SSR loci linked to drought-responsive candidate genes could be useful in MAS.

Osorio C., Wen N., Mejias J., Lui B., Reinbothe S., von Wettstein D., Rustgi S. (2019) Development of wheat genotypes expressing a glutamine-specific endoprotease from barley and a prolyl endopeptidase from Flavobacterium meningosepticum or Pyrococcus furiosus as a potential remedy to celiac disease. Functional & Integrative Genomics. 19:123.

DOI: https://doi.org/10.1007/s10142-018-0632-x

Link: https://link.springer.com/article/10.1007/s10142-018-0632-x#citeas

Resumen

Ubiquitous nature of prolamin proteins dubbed gluten from wheat and allied cereals imposes a major challenge in the treatment of celiac disease, an autoimmune disorder with no known treatment other than abstinence diet. Administration of hydrolytic glutenases as food supplement is an alternative to deliver the therapeutic agents directly to the small intestine, where sensitization of immune system and downstream reactions take place. The aim of the present research was to evaluate the capacity of wheat grain to express and store hydrolytic enzymes capable of gluten detoxification. For this purpose, wheat scutellar calli were biolistically transformed to generate plants expressing a combination of glutenase genes for prolamin detoxification. Digestion of prolamins with barley endoprotease B2 (EP-HvB2) combined with Flavobacterium meningosepticum prolyl endopeptidase (PE-FmPep) or Pyrococcus furiosus prolyl endopeptidase (PE-PfuPep) significantly reduced (up to 67%) the amount of the indigestible gluten peptides of all prolamin families tested. Seven of the 168 generated lines showed inheritance of transgene to the T2 generation. Reversed phase high-performance liquid chromatography of gluten extracts under simulated gastrointestinal conditions allowed the identification of five T2 lines that contained significantly reduced amounts of immunogenic, celiac disease-provoking gliadin peptides. These findings were complemented by the R5 ELISA test results where up to 72% reduction was observed in the content of immunogenic peptides. The developed wheat genotypes open new horizons for treating celiac disease by an intraluminal enzyme therapy without compromising their agronomical performance.

Burgos-Díaz C., Wandersleben T., Olivos M., Lichtin N., Bustamante M., Solans C.. (2019) Food-grade Pickering stabilizers obtained from a protein-rich lupin cultivar (AluProt-CGNA®): Chemical characterization and emulsifying properties. Food Hydrocolloids. 87:847.

DOI:10.1016/j.foodhyd.2018.09.018

Link: https://www.sciencedirect.com/science/article/pii/S0268005X18308555

Resumen

Pickering stabilizers exhibit unique interfacial properties; however, only limited types of these particles are available for the food industry. Therefore, the main aim of this study was to develop a food-grade Pickering stabilizer using a protein isolate obtained from the protein-rich lupin variety AluProt-CGNA® (LPIA). Lupin protein aggregate particles (LP-APs), obtained from LPIA, were produced through a facile and scalable technology based on heat-induced particle formation. LP-APs with high surface charge and partial wettability were effective for stabilizing O/W emulsions. These emulsions were prepared by using high-speed homogenization with LP-APs dispersions. The creaming index, microstructure and physicochemical properties of Pickering emulsions were investigated.

The results showed that LP-APs exhibit great potential to perform as stabilizers for O/W Pickering emulsions (O/W). Additionally, LP-APs exhibited much better interfacial and emulsifying properties than did the unheated LPIA. Heating greatly improved the emulsification performance of protein particles, especially at high concentrations (>3%, w/v). The formed emulsions were highly stable against creaming upon storage over 14 days. These findings are of great importance for the formulation of LP-APs-based emulsions with improved properties (e.g., stable against creaming and coalescence) and will also significantly extend the application of lupin proteins in the food industry.