Browse

You are looking at 71 - 80 of 2,287 items for :

  • Biology and Life Sciences x
  • Materials and Applied Sciences x
  • Refine by Access: All Content x
Clear All

Abstract

‘Patharnakh’ (Pyrus pyrifolia Burm.) (PN), a hard pear and ‘Punjab Beauty’ (Pyrus communis L. × Pyrus pyrifolia Burm.) (PB), a soft pear are dominant low-chill pear cultivars of subtropics of India. Present investigation reports the changes in sugar metabolism and related enzymatic activities in fruits of ‘PN’ and ‘PB’ cultivars harvested at different developmental stages from 45 to 150 days after fruit set. Total soluble sugars, fructose, and sucrose contents were higher in ‘PB’ as compared to ‘PN’ during fruit growth and maturation stages. Total phenols and flavanols increased initially and then showed a decreasing trend towards maturity. Sucrose synthase (SS) and sucrose phosphate synthase (SPS) activities strongly correlated to sucrose content in ‘PN’ but SPS was weakly related in ‘PB’ fruits. Acid and neutral invertases showed a negative correlation with sucrose content in ‘PN’, and a reverse trend in ‘PB’ cultivar was observed. It is concluded that SS and SPS are crucial for sucrose accumulation in ‘PN’, but invertase enzymes are also important for sucrose accumulation in ‘PB’ fruits.

Restricted access

Abstract

Non-alcoholic fatty liver disease is one of the most common chronic liver diseases with unclarified pathomechanism and without evidence-proven therapy. Dietary polyphenols, targeting oxidative stress, are at the center of investigations. Our aim was to examine the effects of a polyphenol rich extract on metal element homeostasis and transmethylation ability in non-alcoholic fatty liver model. A ten-day rat model was used (control group, hyperlipidemic group with fat-rich diet, hyperlipidemic group with fat-rich diet and polyphenol supplementation, N = 8 in each group). The hyperlipidemic diet increased the concentration of the majority of the elements with significantly higher contents of B, Co, Cu, Fe, Mg, Mn, Na, Ni, P, Se, Si, and Zn in the liver. Further elevation of Al, Pb, and Sn concentrations could be observed in polyphenol supplemented animals. The polyphenol supplement unexpectedly decreased the transmethylation ability of the liver (132.00 vs. 114.15 vs. 92.25 HCHO μg g−1) further. The results emphasize the possible role of altered metal and non-metal element concentrations and decreased transmethylation ability in the pathomechanism of fatty liver disease. Dietary supplementation with natural compounds may have undesirable effect as well, there is the necessity to improve the efficacy of polyphenol formulations because of their low oral bioavailability.

Open access
Acta Alimentaria
Authors:
K.O. Bartha
,
L. Csengeri
,
A. Lichthammer
,
A. Erdélyi
,
J. Kubányi
, and
Zs. Szűcs

Abstract

COVID-19 lockdown affects people's daily routine and has an impact on their lifestyle. Recent studies documented associations between body weight changes and children's lifestyle during social isolation. Childhood obesity is associated with a higher risk of COVID-19 severity and mortality. Our aim was to assess the effects of lockdown due to the COVID-19 pandemic on children's sleep, screen time, physical activity, and eating habits. 387 parents of five elementary school students between 16 and 26 June 2020 were interviewed through an online questionnaire. Physical activity level decreased (63.8%), sleep (60.9%) and screen (5.64 ± 3.05 h/day) times and food intake (39.8%) increased. 80.6% of parents reported changes in children's diet: increased consumption of fruits and vegetables (32.4%), breakfast (15.5%), water and sugar-free beverages (17.6%), snacks (40.4%), sugary drinks (9.9%) was observed. Body weight increased in 44.4% of children. The results of the survey conducted under GYERE®-Children's Health Program are in line with the international literature findings: body weight change during the quarantine is significantly associated with food intake, snacking, sugary drinks, and we also found association with fruit and vegetable consumption and lack of breakfast. Effective strategies and electronic health interventions are needed to prevent sedentary lifestyle and obesity during lockdown.

Open access

Abstract

Cassava is used as a staple food in many developing countries despite its low nutrient density. Fortification of cassava diets is needed for the prevention of malnutrition and achievement of food security. Cassava-soybean complementary foods were formulated from natural and solid state fermented cassava complemented with soybean. The proximate composition, physicochemical properties, nutritional quality, and sensory properties of the samples were determined (Table 2). The moisture content (7.51%) and ash (3.81%) content of the solid state fermented (SSF) cassava flour complemented with un-defatted soybean flour was significantly higher (P < 0.05) than of the other samples. Solid state fermentation (SSF) led to the highest reduction in viscosity (from 2,855 to 2,052 cPs). Average weight gain and protein efficiency ratio (PER) of experimental animals fed SSF cassava were the highest. The colour and aroma of SSF diets and that of fermented cassava samples were similar (P > 0.05). The texture of diets from SSF cassava were inferior (P < 0.05) to the other samples. Solid state fermentation of cassava with Rhizopus oligosporus and supplementation with soybean can be used to produce a complementary food that is nutrient dense and nutritionally adequate, although the texture of the product might need to be improved.

Restricted access
Progress in Agricultural Engineering Sciences
Authors:
N. Anter
,
M. Y. Guida
,
M. Kasbaji
,
A. Chennani
,
A. Medaghri-Alaoui
,
E. M. Rakib
, and
A. Hannioui

Abstract

In this scientific paper, thermochemical conversion of redwood (RW) was studied. Using the thermogravimetric analysis' technique (TGA), the thermal behavior of RW samples was examined at four heating rates ranging from 5 to 20 K min−1 in inert atmosphere between 300 and 900 K. Two main objectives have been set for this study; the first one was the determination of the kinetic decomposition parameters of RW (Pinus sylvestris L.), and the second one was the study of the variation of characteristic parameters from the TG-DTG curves of the main RW's components, such as; cellulose, hemicellulose and lignin. The kinetic analysis was performed using three isoconversional methods (Vyazovkin (VYA), Friedman (FR) and Flynn-Wall-Ozawa (FWO)), Avrami theory method and the Integral master-plots (Z(x)/Z(0.5)) method to estimate activation energy (E a ), reaction order (n), pre-exponential factor (A) and model kinetic (f(x)) for the thermal decomposition of cellulose, hemicellulose and lignin components.

The DTG and TG curves showed that three stages identify the thermal decomposition of RW, the first stage corresponds to the decomposition of hemicellulose and the second stage corresponds to the cellulose, while the third stage corresponds to the lignin's decomposition. For the range of conversion degree (x) investigated (0.1 ≤ x ≤ 0.7), the mean values of apparent activation energies for RW biomass were 127.60–130.65 KJ mol−1, 173.74–176.48 KJ mol−1 and 197.21–200.36 KJ mol−1 for hemicellulose, cellulose and lignin, respectively. Through varied temperatures from 550 to 600 K for hemicellulose, from 600 to 650 K for cellulose and from 750 to 800 K for lignin, the corresponding mean values of reaction order (n) were 0.200 for hemicellulose, 0.209 for cellulose and 0.047 for lignin. The pre-exponential factor's average values for three components of RW ranges from 0.08 × 1012 s−1 to 2.5 × 1012 s−1 (A hemicellulose = 1.09 × 1012 s−1), 0.10 × 1014 s−1 to 0.28 × 1014 s−1 (A cellulose = 0.17 × 1014 s−1) and 3.07 × 1016 s−1 to 3.69 × 1016 s−1 (A lignin = 3.33 × 1016 s−1), respectively. The experimental data of RW had overlapped the D 4, D 2 and F 3 in the conversion degree of 10–30%, 30–55% and 55–70% for the three components, respectively.

Open access

Abstract

This study was designed to investigate the effects of green tea on lipid profile, liver tissue damage, and oxidative stress in rats fed a diet including high fructose. Sprague-Dawley rats were randomly divided into four groups: Control (C), Fructose (F), Green Tea (GT), and F+GT. F and F+GT groups were given 20% fructose in the drinking water for eight weeks. Green tea (2 mg kg−1) was administrated to GT and F+GT groups by oral gavage for eight weeks. Biochemical parameters in serum and oxidative stress markers in the liver were analysed. The liver sections were stained with haematoxylin-eosin. As of the 3rd week of the experiment, the body weight of rats in the F group showed a statistically significant increase in comparison with the F+GT group. The serum glucose and triglyceride levels of the F+GT group significantly decreased when compared with the F group. The fructose-induced degenerative changes in the liver were reduced with green tea. Green tea may serve a protective role against hyperlipidaemia and liver injury in rats fed a high fructose diet.

Open access

Abstract

Indigenous yeast strains Kluyveromyces marxianus (MH6), K. marxianus (CH1), and Saccharomyces cerevisiae (C1) were screened for whey beverage production. K. marxianus (MH6) showed significantly higher (P < 0.05) fermentation efficiency (15.2%) as compare to other yeast strains. The conditions optimised for whey fermentation were 16 Brix, pH 5.5, 28 °C, and 72 h without agitation. For fermented whey beverage production, fruits viz., kinnow (Daizy), guava (Allahabad safeda), and mango (Safeda) were blended with whey at different ratios viz., 80:20, 70:30, 60:40, and 50:50. All ratios showed significant differences for biochemical and sensory analysis (P < 0.05), out of which ratios 60:40, 70:30, and 60:40 for whey kinnow, whey mango, and whey guava, respectively, were selected. To enhance the flavour of whey beverage, flavouring agents (cinnamon, cardamom, fennel seeds, and apple essence) were added. A panel of judges assessed all whey beverages on a hedonic scale basis, and cardamom whey guava beverage received the highest score of 8.16. The whey beverages were stored under refrigerated conditions after pasteurisation, and the shelf life was assessed to be 15 days. This study conferred that K. marxianus held the potential for fermented whey fruit blend beverages production and these beverages could be an alternative healthy refreshing substitute for synthetic bottled fruit beverages.

Restricted access
Acta Alimentaria
Authors:
B. Raposa
,
E. Antal
,
J. Macharia
,
M. Pintér
,
N. Rozmann
,
D. Pusztai
,
M. Sugár
, and
D. Bánáti

Abstract

Several misconceptions exist about foods and nutrition. Many believe, that the human body can “acidify”, thus, an “alkaline diet” should be followed. The acid-base balance is a characteristic of a normally functioning human body. Throughout our metabolic processes, acids and substances with acidic pH are produced continuously, which, in the case of a healthy person, does not affect the pH of the human body. In those rare cases, when an overall pH imbalance evolves in the human body due to its life-threatening nature, it requires urgent medical intervention. Furthermore, it cannot be influenced by dietary interventions.

This paper highlights evidence regarding acidification and the acid-base balance, with special attention to certain food groups. Foodstuffs have different specific pH value (acid-base character), they can be acidic, alkaline, or neutral in elemental state. Beside their chemical nature, the effect they have on the human body depends on the mechanism of their metabolism, as well. Diet and ingredients have direct and indirect effects on the human body's intracellular and extracellular compartments (especially blood and urine), still they do not influence its pH significantly.

Alkaline diets were born in the absence of evidence-based information and/or the misunderstanding and wrong interpretation of the available and up-to-date scientific facts. The convictions of consumers and the promotion of the alkaline diet lack the scientific basis, so it can be harmful or even dangerous in the long run.

In summary, scientific evidence on the efficacy or prophylactic effects of an alkaline diet is not available.

Open access

Abstract

To overcome the problems of seasonality and geographical location in fruit production and processing, the production of aseptic semi-finished juice is an excellent solution. Even without refrigeration, aseptic pressing has a shelf life of more than a year, making it possible to produce finished products all year round. The production technology involves the addition of ascorbic acid to the pulp to fix or preserve colour. There is an increasing customer demand for ascorbic acid substitutes on the international market. In Hungary, one of the most important exports is aseptic sour cherry juice. In our work, ascorbic acid used for colour fixation was replaced by acerola concentrate. The anthocyanin content and colour coordinate values (L*, a*, b*, H, C) of aseptically filled sour cherry juice were determined and compared with the control sample during the 12 months of storage.

Open access
Agrokémia és Talajtan
Authors:
Tibor Tóth
,
Tibor Novák
,
András Makó
,
Bence Gallai
,
Szabolcs Czigány
,
Mátyás Árvai
,
János Mészáros
,
Mihály Kocsis
,
Péter László
,
Sándor Koós
, and
Kitti Balog

As a means of assisting the selection of promising soil classification systems, a set of criteria were presented and tested. Inside the studied slightly saline plot World Reference Base (WRB) and Hungarian soil classification (HU) were compared at all four levels in terms of class separability, correlation to biomass, parsimony and homogeneity of classes. WRB surpassed HU in terms of the very important homogeneity of classes only, but HU performed better in terms of class separability, correlation to biomass and parsimony of classes. With many possible classification units WRB categorized the soil into a large number of classes, but 67% and 78% of them were single-profile classes at levels 3 and 4, respectively inside the ca 0.9 km2 area.

Open access