[Osteoprotective effect of bread enriched with protein, dietary fiber, calcium, iron and iodine in hypoestrogen-induced osteoporosis among rats]

The search for new strategies for the prevention and control of osteoporosis is an urgent task. Functional foodstuffs and their components are of particular interest in this regard. The aim was to study the effect of bread enriched with protein, dietary fiber, calcium, iron and iodine on the state of the bone tissue of rats in a model of postmenopausal osteoporosis. Material and methods. The experiment was performed on sexually mature female Wistar rats divided into groups: K - control (sham-operated rats, not ovariectomized); О₃₀ - osteoporosis model (animals were sacrificed 30 days after ovariectomy); groups О₁₂₀ and О₁₂₀₊ - a model of osteoporosis (rats were sacrificed 120 days after ovariectomy). All animals were fed a standard vivary diet. For rats of the О₁₂₀₊ group, from the 40th to the 120th day, enriched bread was included in the diet in an amount of 6 g per 100 g of body weight per day. The bread was fortified with protein (whey protein, blood plasma proteins from farm animals), dietary fiber, calcium (eggshell), iron (purified hemoglobin) and iodized whey protein. Animals of groups K and О₁₂₀ received unfortified bread in the same amount. Blood levels of total calcium (by colorimetric method), gonadotropins, testosterone, and estradiol (by enzyme-linked immunosorbent assay) were analyzed. Microtomographic evaluation of the architecture and mineral density of the trabecular part of the femur and lumbar vertebrae was performed. Histomorphological analysis of the uterus and femur of animals was performed. Results and discussion. In animals of the О₁₂₀₊ group, in comparison with the О₁₂₀ sample, there was a decrease in blood testosterone and a marked compensatory release of follicle-stimulating hormone, while no changes were detected in the concentration of estradiol and the state of the uterus atrophied against the background of ovariectomy. There was an increase in the trabecular mineral density of the femur and lumbar vertebrae. The proportion of bone trabeculae in the total volume of the femoral metaphysis (BV/TV) in animals of the О₁₂₀₊ sample was 12.5±0.66% compared to 10.4±0.52% in the О₁₂₀ group. The values of the structural model index (SMI) reflecting the loss of bone strength and the trabecularity coefficient (TbPf) in О₁₂₀₊ rats (1.44±0.07 and 5.96±0.29 1/mm) were significantly lower than these parameters in the О₁₂₀ group (1.74±0.08; 9.13±0.46 1/mm, р<0.05). The micro-architectural structure of the femur in the О₁₂₀₊ group of rats was close to that of the О₃₀ sample, which serves as a model of the early stage of osteoporosis (SMI 1.42±0.07; TbPf 5.55±0.28 1/mm). The percentage of bone resorption perimeter and the number of osteoclasts in the О₁₂₀₊ femoral trabeculae were lower than in the О₁₂₀ group. In the О₁₂₀₊ group, active osteoblasts were observed in a significant part of the resorption cavities. Cell differentiation more was observed in the osteogenic direction than in the adipogenic direction. Conclusion. Bread enriched with protein, fiber, calcium, iron and iodine, effectively weakens osteoporosis induced by ovariectomy in rats. Its inclusion in the diet may be beneficial for the prevention and treatment of systemic postmenopausal osteoporosis.

[The influence of the drying method for food properties and hypolidemic potential of oyster mushrooms (Pleurotus ostreatus)]

The aim of this research was to study the influence of two drying methods: freeze-drying sublimation and dry-air drying on the selected nutritional properties and hypolipidemic potential of fruiting bodies of oyster mushroom (Pleurotus ostreatus). The criteria for evaluation of the food properties were the color, the morphological structure, regidratation capacity, the total level of soluble proteins, fats, polysaccharides, free amino acids and monosaccharides. Lipid-lowering potential of oyster mushroom was evaluated by the concentration of lovastatin and the level of antioxidant activity. It has been experimentally revealed that the value of optical density of hydro-alcohol extracts of dried oyster mushrooms at a wavelength of 295 nm most clearly characterized its color which intensity was almost twice less in sublimated mushrooms, than шт the sample dried by dry-air method. Histological data showed that dry-air drying lead to the destruction of the mushroom cells and to the formation of a dense layered structure. Sublimation drying preserved the ordered cell structure and provided less deformation and shrinkage of the tissues. Using X-ray microtomography it was reported that freeze-dried mushrooms had uniform pore volume distribution. Dry-air dehydration method lead to the formation of larger cavities. The average percentage of the open pores was: 29.41±0.52% (after dry-air method), 11.10±0.41% (after freeze-drying method). Respectively the number of closed pores, which reflected the true value of porosity, was 0.99±0.01 and 1.75±0.01%. Structural differences of the samples of the dry oyster mushroom combined with their unequal hydration ability. Indicator of rehydration for oyster mushroom dried by sublimation method was 5.4±0.1, and for samples obtained by dry-air method it was 3.2±0.1. Respectively the average time of maximum water absorption was 22.7±1.8 and 45.3±2.9 minutes. It was found that the freeze-drying sublimation conditions were more conducive for the preservation of the biologically active protein and polysaccharide components of oyster mushrooms and on the other hand dry-air drying method increased the nutritional value of oyster mushrooms due to the reactions of polysaccharides autohydrolysis. The number of proteins and polysaccharides of the Oyster mushrooms samples dried by dry-air method and freeze-drying method was 72.0% and 56.0% respectively. Concentrations of free amino acids and glucose in the samples dried by freeze-drying and dry-air methods were 11.60±0.31%; 175.20±6.10 mg% and 7.00±0.28%; 144.0±5.7 mg% respectively. It has been experimentally recorded that the conditions of freeze drying were optimal in terms of ensuring the preservation of the content of natural statin and the antioxidant capacity of oyster mushrooms that provided its hypolipidemic potential. The amount of lovastatin in an the freeze-dried samples was 342±9.0 mg/kg, and was significantly higher than in the samples received by dry-air method - 190±6.0 mg/kg. The level of antioxidant activity of the oyster mushrooms samples were respectively 3.83±0.02 against 2.0±0.03 mmol/100 g. The conducted researches proved that for the production of dry oyster mushroom as a potential biologically active feedstock for the functional food products with lipid-regulating directivity the choice of the drying method had a fundamental importance.