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Abstract
The main objectives of the present study were to investigate the physical attributes and chemical characteristics of dried apple cubes. The apple cubes were dried in vacuum and infrared dryers at 40 °C and freeze dryer individually and in combination. The physical properties – texture and rehydration – of vacuum drying-assisted freeze-dried apple dices were close to the freeze-dried products. The hardness of vacuum drying-assisted freeze-dried apples was better, by at least 15.8%, than those dried by infrared-freeze, but rehydration capacities were similar. The freeze-dried control samples achieved a lower water activity (0.145) in comparison with infrared, vacuum, and combined dried ones. The infrared-freeze-dried samples retained 3.6 and 11.6% more polyphenols and antioxidant capacity than samples prepared by the other methods. The ascorbic acid content of the freeze-dried samples was significantly higher by about 59% than that of the hybrid dried samples.
Abstract
The 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.
Abstract
The 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.
Abstract
As 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.
Abstract
In our study, using a combination of eye-tracking parameter analysis and the van Westendorp method, we investigate whether participants pay more attention to products that they perceive as more expensive or to those that they prefer in the ranking process. The experiment involved 50 participants, a questionnaire with ranking and pricing tasks, and an eye-tracking measurement. Three wine varieties (Irsai Olivér, Rosé and Merlot-Shiraz) and three different label alternatives were tested. When comparing the results of the ranking and the pricing tasks, the product that is considered more expensive is not always the one that is most appealing to the participants. If we compare the results from the analysis of the eye-tracking parameters and the pricing, we can say that in all cases the labels that received the most visual attention were those that were priced more expensively by the participants.
Abstract
Thermobifida alba is the mesophilic member of the Thermobifida genus, the genome and enzyme sets of which have not been described and published yet. Thermobifida strains are thermotolerant actinomycete, which possess wide sets of cellulose and hemicellulose hydrolysing enzymes. Previously, three endomannanases (Man5ATh, Man5ATc, and Man5AThf) of thermobifidas were cloned and investigated, and hereby the endomannanase of T. alba DSM 43795 is described. All four endomannanases belong to the glycoside hydrolase family 5, their sizes are around 50–55 kDa. Their structure consists of a catalytic domain and a carbohydrate binding module, while there is an interdomain linker region in-between consisting repetitive tetrapeptide motifs (eg.: PPTEPTD-Ta, PTDP-Tc, TEEP-Tf, DPGT-Th). The pH optima of Man5A enzymes from T. alba, Thermobifida halotolerans, Thermobifida cellulosilytica, and Thermobifida fusca are slightly different (6.5, 7.0, 7.5, and 8.0, respectively), however, the temperature optima of the enzymes were detected within a wider range of 65–75 °C. In this research, Man5ATa exhibited the lowest Michaelis-Menten constant (KM) (0.13 mM) on LBG-mannan substrate, while others shared similar kinetic parameters: 0.9–1.7 mM of KM. Despite the high sequence similarity of the investigated mannanases, they exhibit different temperature stability parameters. These different functional characteristics can be advantageous for industrial applications producing biologically active, oligomannan prebiotics under different conditions.
Abstract
In 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.
Abstract
This 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.
Abstract
In the modern era, nutraceutical properties of horticultural crops are indispensable to determine their adaptability to different agro-ecological regions. The present study exploits the potential of mulches (P: plastic mulch; S: straw mulch; N: No mulch) in relation to drip irrigation (I1: 100%, I2: 80%, I3: 60% of crop evapotranspiration (Etc)), and fertigation (F1: 100%, F2: 80%, F3: 60% of recommended dose of fertilizer (RDF): 125 kg N, 62.5 Kg P2O5, 62.5 kg K2O per ha) on Pak choi at three maturity stages in the North West region of India. Plant fresh weight was the highest at 55 days after transplanting (DAT); however, maximum soil plant analysis development (SPAD) values were registered at 45 DAT. Antioxidant activity, FRAP, DPPH, phenols, flavanols, total sugars, ascorbic acid, free amino acids, and irrigation water use efficiency were observed significantly higher in plants grown on plastic mulch at different levels of irrigation and fertigation. It is envisioned that Pak choi plants had the highest nutritional value at 45 DAT from plots mulched with silver-black, irrigated at 80% Etc, and fertigated at 100% RDF. The nutrient enriched plants are used for green salad and as ingredients for the preparation of many recipes in the semi-arid and sub-tropic areas of India.
Abstract
This paper explores the prediction of the soluble solid content (SSC) in the visible and near-infrared (400–1,000 nm) regions of Baise mango. Hyperspectral images of Baise mangoes with wavelengths of 400–1,000 nm were obtained using a hyperspectral imaging system. Multiple scatter correction (MSC) was chosen to remove the effect of noise on the accuracy of the partial least squares (PLS) regression model. On this basis, the characteristic wavelengths of mango SSC were selected using the competitive adaptive reweighted sampling (CARS), genetic algorithm (GA), uninformative variable elimination (UVE), and combined CARS + GA-SPA, CARS + UVE-SPA, and GA + UVE-SPA characteristic wavelength methods. The results show that the combined MSC-CARS + GA-SPA-PLS algorithm can reduce redundant information and improve the computational efficiency, so it is an effective method to predict the SSC of mangoes.
