AbstractEffect of edible coatings based on zedo gum (ZG) containing thyme (Thymus vulgaris) essential oil (TEO) and cinnamon (Cinnamomum verum) extract (CAE) on the quality and proteolysis of cheddar cheese was investigated. Four treatments were prepared using different coating formulas including: C (coated cheese with paraffin and wax mixture as commercial coating), Z treatment (coated cheese with ZG solution), TEO treatment (coated cheese with TEO), and CAE treatment (coated cheese with CAE). The results showed that the highest moisture content and proteolysis indices were related to sample C; the lowest moisture content and number of starter lactic acid bacteria (SLAB) and the highest protein content, FDM content, proteolysis indices and number of non-starter lactic acid bacteria (NSLAB) were related to sample Z; while the TEO and CAE treatments showed similar values. Also, TEO and CAE had an inhibitory effect on growth of moulds and yeasts, without affecting NSLAB and SLAB. Therefore, instead of commercial coating, zedo gum containing T. vulgaris essential oil or C. verum extract can be used as active coating on cheddar cheese.

AbstractThe popularity of sweet potatoes in Central Europe has been increasing recently, mainly the high-quality, perfect, fresh tubers are in demand. However, out of class grade tubers could be marketed in dried, grounded form as sweet potato flour.The aim of this study was to characterise some important nutritional properties of flours of three sweet potato genotypes with different tuber colours (white, purple, and orange) and to investigate how this raw material affects the rheological properties of sweet potato-wheat flour blends.Dietary fibres are present in sweet potatoes in a significant proportion, orange coloured flour showed the highest values. The main free sugars were sucrose, glucose, and fructose, but sucrose was the dominant one. Antioxidant capacity and total phenolic content also varied considerably, the purple flour had the highest values. Mineral composition showed significant variability, the purple flour contained the highest level of minerals. It was confirmed that adding sweet potato flour to wheat flour affected its rheological properties, however in a varied manner. For the orange flour these properties have lightly decreased, though it had no significant effect on dough quality, while the white and purple flours with a dosage of 5, 10 and 15% could improve the dough behaviour. Thus, sweet potato in this form is a valuable raw material.

AbstractThe aim of our research was to study the water and ethanol extractable polyphenols of stinging nettle (Urtica dioica L.) harvested in different seasons and to determine their antimicrobial activity against certain human pathogenic and food spoiling bacteria and yeasts.Our results indicate that the spring leaf extracts had higher polyphenol contents than the root one; however, close to the end of the vegetation period these values decreased considerably in both leaves and roots. Detection and quantification of the most abundant phenolic compounds in the spring extracts by HPLC revealed the occurrence of 12 different phenol carboxylic acids and flavonoids. Flavonoid compounds were more abundant than phenol carboxylic acids in the leaves; however, their proportion was equal in the case of the roots. Nettle leaf extracts had remarkable antimicrobial activity, the spring extracts were more efficient than the autumn ones. Escherichia coli and Staphylococcus aureus were sensitive to every leaf extract, while Listeria monocytogenes and Pseudomonas aeruginosa had reduced but remarkable sensitivity patterns. Among the yeasts, Candida glabrata was strongly inhibited by the aqueous leaf extracts. Most of the strains were insensitive to the root extracts, although Enterococcus faecalis was inhibited by the root and not the leaf extracts.

AbstractAs a principal pigment in plants, chlorophyll a (Chl a) is widely used to evaluate quality changes and senescence process during storage of leafy vegetables. The determination of Chl a in plant extracts by spectrophotometric methods using various empirical equations is often unreliable. Considering the sensitivity of fluorescence detection, we report here a simple, inexpensive spectrofluorimetric method that can detect and quantify Chl a in plant extracts. The fluorescence standard used for the quantitative determination of Chl a was isolated in our laboratory from the extract of Anthrospira platensis (Spirulina). The method proved to be reliable, fast, and low cost in a study of the influence of the most commonly used domestic storage conditions on Chl a degradation in fresh-cut arugula.

AbstractIn the study, suitability of porridge, bun, and salad prepared from processed pearl millet FBC16 and sorghum PSC4 had been evaluated organoleptically by a panel of semi-trained judges and 25 non-insulin dependent diabetes mellitus subjects. Organoleptically, germinated pearl millet was found to be more suitable for porridge (50%) and salad (100%), while puffed sorghum was best suitable for bun (15%) preparation. Prepared porridge had significantly (P ≤ 0.05) higher protein (16.9%) and total phenols (178.8 mg GAE/100 g) contents and antioxidant capacity (1,036 mg TE/100 g) than control. The dietary fibre and in vitro starch digestibility of composite porridge and bun increased significantly (P ≤ 0.05). Most acceptable composition of porridge, bun, and salad had low glycaemic index (17.64–26.79) and medium to low glycaemic load (8.82–13.40). Suitability of pearl millet and sorghum using appropriate processing techniques (germination and puffing) is recommended for preparation of indigenous food products especially for diabetics.

AbstractThis study aimed to investigate the anti-obesity potential of camel colostrum and milk proteins as well as their enzymatic hydrolysates. Camel colostrum and milk proteins were treated using six proteolytic enzymes (pepsin, trypsin, α-chymotrypsin, pancreatin, papain, and pronase). The degree of hydrolysis was measured to verify the degradation of proteins. The in vitro anti-obesity activity was evaluated using the pancreatic lipase inhibitory assay. Camel colostrum and milk protein hydrolysates exhibited different degrees of hydrolysis ranging from 17.69 to 43.97%. The protein content varied between 56.08–61.95% and 37.39–41.72% for camel colostrum and milk protein hydrolysates, respectively. The hydrolysates displayed significantly higher anti-obesity activity than the undigested proteins at all tested concentrations (P < 0.05). Colostrum protein hydrolysate generated with pancreatin had the highest anti-obesity potential (59.92%). These results suggest that colostrum and milk protein hydrolysates could be used to formulate functional foods and nutraceuticals.

AbstractIn this study, a water-soluble novel polysaccharide called TPS was successfully prepared and isolated from Liubao tea. The optimal extraction conditions resulted in a yield of 10.70% for the crude TPS. The purified TPS exhibited unique physicochemical properties and structural characteristics. It was identified as an acidic polysaccharide with trace binding proteins, with a →4)-α-D-Galp-(1→) residue. The purified TPS had a dense and uneven appearance, potential crystallisation characteristics, and structural stability. Importantly, it demonstrated the ability to inhibit glucose transport in Caco-2 cells by down-regulating the expression of sodium/glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2), leading to a hypoglycemic effect. These findings highlight the potential of TPS from Liubao tea as a functional food or additive with hypoglycaemic properties.

AbstractFood allergies became a major public health and food safety interest in the past decades as their prevalence is increasing, and their only available treatment is a strict elimination diet that necessitates appropriate food labelling regulations. While such regulations are available worldwide, most of them are not taking into account inadvertent allergen cross-contamination and they usually do not define threshold doses that could support the industry in their endeavour to provide reliable food labels for allergic consumers. This resulted in the proliferation of the “may contain” type precautionary allergen labelling (PAL), which is voluntary and is intended to warn consumers for potential unintended contamination with an otherwise undeclared allergen. As this kind of labelling is hardly ever based on actual risk assessment, it puts both the industry and the consumer into a difficult position. A promising tool towards the solution of this problem could be allergen threshold doses based on clinical data, which are becoming increasingly available. This review intends to present this process, the new ways of improved risk assessment it opens, and its implications for food analysis.

AbstractSynthesis of nanoparticles can be long and costly processes using physical and chemical methods. Biological synthesis of nanoparticles is known to be cheaper and easier than other methods. In this study, silver nanoparticles (AgNP) were obtained by biological synthesis, also known as green synthesis, using Sorghum bicolor var. technicum (Körn) Stapf ex Holland seed extract, popularly known as sorghum. AgNPs were characterised by SEM, EDS, TEM, FT-IR, and UV-Vis Spectroscopy. SEM images confirmed that the shape of AgNPs was spherical. TEM analysis showed that the average sizes of AgNPs ranged from 51 to 56 nm. EDS analysis confirmed the presence of AgNPs by detecting a silver ion peak at 3 KeV. UV-Vis spectroscopy analyses indicated that the brown-burgundy colour of AgNPs exhibited maximum absorbance at 450 nm. The biological activities of the extract and AgNPs were investigated through antimicrobial, antibiofilm, antioxidant, mutagenic, and DNA cleavage activity analyses. The extract exhibited the highest MIC value against Gram-positive bacterium Bacillus subtilis (0.62 μg mL−1), whereas AgNPs demonstrated the highest antimicrobial activity specifically against Gram-negative bacterium Escherichia coli (0.31 μg mL−1). The antibiofilm results revealed that the extract displayed the highest percentage of biofilm inhibition against B. subtilis, while AgNPs exhibited notable efficacy against both Candida albicans yeast and Pseudomonas aeruginosa bacterium. The antioxidant activities were evaluated using DPPH• and ABTS•+ methods, and it was determined that both samples had high antioxidant activity. Mutagenicity of the extract and AgNPs were evaluated by the Ames/Salmonella test using two strains of Salmonella typhimurium (TA98 and TA100). The mutagenic activity of the extract increased depending on the concentration for both strains, while AgNP did not show mutagenicity at any concentration. The agarose gel electrophoresis method showed that the extract and AgNPs cleaved DNA in the presence of an oxidising agent.