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The effect of vacuum cooking on enteral food made from fresh and semi-finished ingredients
2017
Ozola, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kampuse, S., Latvia Univ. of Agriculture, Jelgava (Latvia)
Enteral feeding also known as enteral nutrition is nutrient delivery into the stomach. Products for enteral nutrition are a specific group of products designed to provide nutrients to the human body in case of various diseases and after surgery, when the daily intake of the product is affected. Today market offers special dietetic products, which are supplemented with synthetic vitamins and minerals, which bioavailability in the body is lower than that of natural organic complexes. Therefore it is important to develop special dietetic products from natural raw materials. The aim of this study was to evaluate the effect of vacuum cooking on the content of bioactive compounds, soluble solids, pH and shelf life of enteral food made from fresh and semi-finished (heated) fruit and vegetable juices. For this research enteral food was made using fresh or semi-finished fruit and vegetable juices. Products were vacuum cooked in 0.02 MPa pressure, with boiling point 67 °C, and 0.06 MPa pressure at 79 °C, withstander for 15 min. All samples were stored at room temperature and tested for their content of vitamin C, total carotenoids, anthocyanins, total phenols and antioxidant activity and microbiological safety, as control untreated enteral food samples were used. The obtained data showed that samples made from semi-finished juices have higher contents of vitamin C and total carotenoids and anthocyanins than samples prepared from fresh juices, but this wasn’t observed with content of total phenols and antiradical scavenging activity (DPPH), where the type of ingredients used for sample preparation had no significant effect.
显示更多 [+] 显示较少 [-]Effect of high pressure processing on microbial load in pork
2017
Sazonova, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Galoburda, R., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gramatina, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Fresh meat is a highly perishable product due to its biological composition as it serves as an ideal environment for the growth and propagation of microorganisms and common food-borne pathogens. High pressure processing (HPP) is a cold pasteurization treatment to extend shelf-life while preserving the sensory and nutritional characteristics of the product. The aim of this research was to evaluate the effects of HPP on the fresh porcine Musculus longissimus lumborum microbial load and related physical properties (pH, water activity aw, and moisture content). Vacuum packed meat samples were treated at 50, 100, 200, 300, 400, and 500 MPa for 1, 5, and 15 min in a high-pressure processor ISO-Lab S-FL-100-250-09-W (Stansted Fluid Power Ltd., UK). Pressure treatment above 300 MPa resulted in a significant (p is less than 0.05) decrease of total plate count. However, the studied pressurizing time had no significant effect on microbial lethality at the same pressure applied. Other important parameters such as water activity, moisture, and pH were determined as they directly affect microorganism growth and resistance to pressure. A slight increase in pork pH was observed with increased pressure. No significant changes in water activity and moisture content were observed as a result of high pressure treatment. For future researches it would be important to evaluate the dynamics of microbial growth during storing as part of cells after pressure treatment are injured and not eliminated immediately; therefore, microbial count may further decrease during cold storage.
显示更多 [+] 显示较少 [-]The comparison of the spray-drying and freeze-drying techniques for camel milk: a review
2020
Tastemirova, U., Almaty Technological Univ. (Kazakhstan) | Ciprovica, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Shingisov, A., M. Auezov South-Kazakhstan State Univ., Shymkent (Kazakhstan)
The aim of the present study was to analyse and compare camel milk powder quality and functional properties produced with spray-drying and freeze-drying techniques. Freeze-drying is recognized as an advanced method for the production of high-quality dried products, but it has been a costly process for production of camel milk powder. Spray-drying and freeze-drying of camel’s milk demonstrated that the nutritional characteristics of this product basically remained unchanged compared to fresh milk. The differences were found analysing flowability, solubility and hygroscopicity of camel milk powder samples obtained with freeze-drying and spray-drying technique. Analysed quality indices of camel milk demonstrated that spray-drying has lower impact on camel milk powder physical properties in comparison with freeze-drying.
显示更多 [+] 显示较少 [-]α-amylase activity in freeze-dried and spray-dried honey
2020
Keke, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Cinkmanis, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Honey is a naturally supersaturated sugar solution, which tends to crystallize. The crystallization of honey can lead to unwanted fermentation that can have a negative impact to honey quality. The production of honey powder could be an alternative method to prevent honey from fermentation. Honey powder could be used as alternative substitute to liquid honey that would allow to use this product more widely in the food industry. α-amylase activity is one of the most important parameters to evaluate the quality of honey. The aim of this study was to investigate the effect of freeze-drying and spray-drying on honey α-amylase activity. Detection of α-amylase activity was carried out by spectrophotometric method. High-performance liquid chromatography was used to determine the content of hydroxymethylfurfural in the powders. The obtained results showed that both drying methods had a negative impact to the enzyme activity in the samples. The lowest activity of α-amylase (8.3 DN) was measured in the spray-dried honey powder. Concentration of hydroxymethylfurfural (HMF) in the powders did not exceed required concentration 40 mg kgE−1.
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