Isolation and catalytic actions of polyphenoloxidase from sunflower seeds (Helianthus annuus)

In the last few decades, biotechnological applications of phenoloxidase enzymes have become an area of significant interest. In this study, sunflower seeds, seedlings and defatted mill cake were investigated as possible plant source of polyphenoloxidase (PPO). Noticeable variation of chlorogenic acid concentration in each raw material has undoubtedly proven that only sunflower seedlings have significant amounts of active PPO. The activity of the enzymes was assessed by measuring the molar decrease of caffeic acid. Isolated protein powders from each raw material confirmed the presence of PPO only in the seedlings. Catalytic action of the PPO of seedlings was compared to that of the commercial laccase from Trametes versicolor. Sunflower PPO was selectively active on caffeic and chlorogenic acids, less active on ferulic acid and not active on mono-phenols and gallic acid. Conversely, laccase was highly active on all the assessed phenols. PPO activity was good in a large range of pH (4–8), whilst it was approximately halved in solutions containing 35% ethyl alcohol (v/v), 500 mg L⁻¹ citric acid and finally 200 mg L⁻¹ sulphur dioxide. In conclusion, sunflower seedlings can be considered a potential and interesting plant source of PPO. Sunflower PPO could be used to oxidise selectively o-diphenols, for example in alcoholic and nonalcoholic beverages.     

In vitro gastrointestinal digestion of the major peach allergen Pru p 3, a lipid transfer protein: Molecular characterization of the products and assessment of their IgE binding abilities

A simulated gastrointestinal digestion has been carried out on purified peach lipid transfer protein, one of the main allergens among the population of the Mediterranean area and the major allergen of peach allergic patients. The percentage of intact protein, after extensive digestion, measured by comparison with a non‐digestible peptide analogue used as internal standard, was found to be about one‐third of the original protein content. The peptides formed in digested fraction were characterized by means of LC/MS. The products of the digestion essentially derived from trypsin action, whereas the protein appeared to be resistant to pepsin and chymotrypsin. The identified peptides could be classified as low molecular weight and high molecular weight peptides. The latter consisted of the full protein, with the disulfide bridges still intact, deprived of the smaller peptides. The different digestion products, including the high and low molecular weight peptides, were purified by LC and assessed, together with the intact protein, by dot‐blot analysis with sera of allergic patients, allowing to estimate their potential allergenicity. The intact protein and the high molecular weight peptides were found to be recognized by patients' sera, whereas the small peptides were found to be not reactive.     

A New Class of 3′‐Sulfonyl BINAPHOS Ligands: Modulation of Activity and Selectivity in Asymmetric Palladium‐Catalysed Hydrophosphorylation of Styrene

Palladium‐catalysed monophosphorylation of (R)‐2,2′‐bisperfluoroalkanesulfonates of BINOL (R^F=CF₃ or C₄F₉) by a diaryl phosphinate [Ar₂P(O)H] followed by phosphine oxide reduction (Cl₃SiH) then lithium diisopropylamide‐mediated anionic thia‐Fries rearrangement furnishes enantiomerically‐pure (R)‐2′‐diarylphosphino‐2′‐hydroxy‐3′‐perfluoralkanesulfonyl‐1,1′‐binaphthalenes [(R)‐ 8ab and (R)‐ 8g–j ], which can be further diversified by Grignard reagent (RMgX)‐mediated CF₃‐displacement [→(R)‐ 8c–f ]. Coupling of (R)‐ 8a–j with (S)‐1,1′‐binaphthalene‐2,2′‐dioxychlorophosphine (S)‐ 9 generates 3′‐sulfonyl BINAPHOS ligands (R,S)‐ 10a–j in good yields (43–82%). These new ligands are of utlility in the asymmetric hydrophosphonylation of styrene ( 1 ) by 4,4,5,5‐tetramethyl‐1,3,2‐dioxaphospholane 2‐oxide ( 2 ), for which a combination of the chiral ligands with either [Pd(Cp)(allyl)] or [Pd(allyl)(MeCN)₂]⁺/NaCH(CO₂Me)₂ proves to be a convenient and active pre‐catalyst system. A combination of an electron‐rich phosphine moiety and an electron‐deficient 3′‐sulfone moiety provides the best enantioselectivity to date for this process, affording the branched 2‐phenethenephosphonate, (−)‐iso‐ 3 , in up to 74% ee with ligand (R,S)‐ 10i , where Ar=p‐anisyl and the 3′‐SO₂R group is triflone.     

Managing ochratoxin A risk in the grape-wine food chain

The main source of ochratoxin A (OTA) in the wine food chain is the infection of grapes by "black aspergilli" in the field. OTA-producing black aspergilli include principally Aspergillus carbonarius, followed by A. niger and possibly A. tubingensis. They are opportunistic fungi that develop particularly on damaged berries at ripening, although they may occur and form OTA on grapes from veraison to harvest. Climatic conditions (high humidity and temperature) and geographical location are important factors favouring OTA accumulation in grape berries. The severity of aspergillus rot is influenced by excessive irrigation and rainfall prior to harvest, which causes berry splitting. In addition, berry wounds caused by insect attack provide preferential entries for black aspergilli. High OTA levels occur in grapes severely damaged by the grape moth, Lobesia botrana, particularly in Mediterranean areas. Some grape varieties display greater susceptibility to aspergillus rot due to intrinsic genetic characteristics and bunch conformation (i.e. compact>sparse). Control measures for toxigenic mycoflora in the vineyards must consider these critical control points. Proper fungicidal and insecticidal treatments can reduce OTA contamination. Nevertheless, knowledge about the fate of OTA and its distribution in wine and winery by-products is important to manage OTA risk in contaminated stock. In our wine-making experiments, only 4% of the OTA present in grapes remained in the wine--the majority is retained in pressed grape pomaces. OTA concentration remained unchanged in wine after a 1-year aging as well as in all liquid fractions collected during vinification (i.e. must, free run wine, and wine after first and second decantation). Activated carbon can reduce OTA levels in wine but negatively affects wine quality.     

Influence of tef flour and its association with other flours on the nutritional,technological, and sensory quality of bakery products

The objective of this study was to investigate chemical, technological, and sensory quality of tef in products made exclusively with tef flour and tef flour associated with other flours. The selection of the studies and the extraction of information were carried out through research in several databases. Tef flour was used in cakes, cookies, breads, cupcakes, muffins, and extruded snacks. Bread was the most evaluated product with tef flour associated with other flours or exclusively. Most of the outcomes were with tef (5–50%) associated with other flours. Increased levels of fibers, minerals, antioxidant capacity, and flavonoids were noted according to the percentage of tef. Technological characteristics demonstrated that these products showed intermediate final quality, due to the characteristics of volume, specific volume, firmness, and luminosity. Regarding sensory quality, studies that used (5–35%) tef flour associated with other flours were well-accepted.     

A lightweight and cost effective edge intelligence architecture based on containerization technology

World Wide Web - The integration of Cloud computing and Internet of Things led to rapid growth in the edge computing field. This would not be achievable without combining the data centers’...     

FNDC5/Irisin System in Neuroinflammation and Neurodegenerative Diseases: Update and Novel Perspective

Irisin, the circulating peptide originating from fibronectin type III domain-containing protein 5 (FNDC5), is mainly expressed by muscle fibers under peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) control during exercise. In addition to several beneficial effects on health, physical activity positively affects nervous system functioning, particularly the hippocampus, resulting in amelioration of cognition impairments. Recently, FNDC5/irisin detection in hippocampal neurons and the presence of irisin in the cerebrospinal fluid opened a new intriguing chapter in irisin history. Interestingly, in the hippocampus of mice, exercise increases FNDC5 levels and upregulates brain-derived neurotrophic factor (BDNF) expression. BDNF, displaying neuroprotection and anti-inflammatory effects, is mainly produced by microglia and astrocytes. In this review, we discuss how these glial cells can morphologically and functionally switch during neuroinflammation by modulating the expression of a plethora of neuroprotective or neurotoxic factors. We also focus on studies investigating the irisin role in neurodegenerative diseases (ND). The emerging involvement of irisin as a mediator of the multiple positive effects of exercise on the brain needs further studies to better deepen this issue and the potential use in therapeutic approaches for neuroinflammation and ND.     

A comparison of three multidisciplinarity indices based on the diversity of Scopus subject areas of authors’ documents,their bibliography and their citing papers

Scientometrics - In this paper, we compare the distribution of Elsevier Scopus subject areas of authors’ documents, their bibliographical references and their citing documents. We compute the...