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Effect of Physical Osmosis Methods on Quality of Tilapia Fillets Processed by Heat Pump Drying

Abstract

In order to achieve the influence of different pretreatment methods on heat pump dried tilapia fillets, the effects of trehalose, ultrasound-assisted and freeze-thaw cycle assisted osmotic dehydration on the color, rehydration, texture and Ca2+-ATPase activity were investigated. Tilapia fillets (100 mm length × 50 mm width × 5 mm height) were first osmoconcentrated in a trehalose solution combined with 4°C under atmospheric pressure for 1 h, different power of ultrasound and freeze-thawing respectively, then heat pump dried. The results showed that under the same drying method, the comprehensive score of ultrasound in 400 Watt was best, compared to freeze-thaw, the ultrasound pretreatment had a significant (p<0.05) effect on the color and Ca2+-ATPase activity, but had no significant (p>0.05) effect on the rehydration and texture. However, both of them significantly (p<0.05) affected the quality in comparison to that of osmosis at 4°C. It indicates that suitable ultrasonic pretreatment conditions improve the quality of dried products effectively and the conclusion of this research provides reference for heat pump dried similar products.

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Organoleptic parameters of meat from cows of two age categories depending on marbling

Abstract

The aim of the experiment was to compare the sensory characteristics of meat from cows of two age categories and depending on to the degree of marbling. Slaughter cows were divided into two age categories: up to 4 years of age and over 4 years of age. Meat samples from m. longissimus dorsi for tasting were taken from the right carcass halves between rib 9 to 11. The marbling degree was evaluated according to a 10 point scale (1 - very strong marbling, 10 - virtually no marbling or only traces). A sensory evaluation of the meat was carried out on day 7 after the slaughter of the animals. Meat samples were stored for 7 days and then they were grilled to evaluate their flavour, taste, tenderness and juiciness (degree 1 - without flavour, taste, tenderness, juiciness, degree 5 - very high flavour, tenderness, taste, and juiciness). We also set a score for the shear force of the grilled meat in our device Texture Analyser. There are no significant differences in sensory evaluation between the categories in relation to meat marbling, which would indicate better or worse sensory evaluation of meat. With the characteristic shear force of the grilled meat there were more favourable results at all levels of marbling in category up to 4 years of age.

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Stem cracks of Norway spruce (Picea abies (L.) Karst.) provenances in Western Latvia

Abstract

Stem cracks are damaging for timber quality and can reduce the monetary value of a tree both directly and indirectly: serving as gateway for fungal infections. Aim of the study was to assess the influence of tree dimensions and seed origin on the frequency of stem crack for Norway spruce. The study was carried out in two contiguous provenance trials (material from 12 countries), established in 1972 and 1975 in Western Latvia. Stem cracking was assessed using five-score scale. Most of the affected trees (90%) had very light or light damage. There was no relation of diameter at breast height to incidence of stem cracks. Analysis revealed a significant provenance effect on occurrence of stem cracks. Russian provenances tended to have lower risk of stem cracking and relatively narrow variation within the region, while Baltic and Ukrainian origins had wide range of stem cracking, having best as well as worst provenances in terms of cracking. Overall it is possible to select fast growing provenances with relatively low incidence of stem cracks.

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The Comparative Efficiency Analysis of EU Members Agriculture Sectors

Abstract

Production economics forms a very important part of an enormous range of economic theory. Agricultural production is no exception. When evaluating the competitiveness of the multifunctional agriculture, it is necessary to use the measure of efficiency instead of productivity. The conception of the efficiency is explained and the methods for measurement are provided. The authors discuss the methods of Stochastic Frontier Approach (SFA), Free Disposal Hull (FDH) and Data Envelopment Analysis (DEA) that are particularly useful for multi-criterial evaluation of multifunctional processes. Those methods assign an efficiency score to each Decision Making Unit (DMU) based on how well it transforms a given set of inputs into outputs. Most studies have only focused on application of DEA method for assesment of the efficiency of agriculture farms. There is still a need on applications for sectors. This paper provides an examination of the applicability of DEA method to agriculture sectors efficiency measurement. By applying mathematical models, which are based on the DEA, the efficiency of agriculture in each EU country was evaluated.

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Effect of Brewer’s Spent Grain Addition on Properties of Corn Extrudates with an Increased Dietary Fibre Content

The effect of brewer’s spent grain addition (5, 10, 15 and 20% w/w) on selected properties of extrudates produced from corn grits with various moisture contents (12.5%, 13.5%, 14.5% and 15.5%) was analysed in this study. It was shown that an addition of brewer’s spent grain (BSG) to extrudates reduces expansion and increases density of the product. The changes are dependent on raw material moisture content. A higher addition of brewer’s spent grain is reflected in higher values of Water Absorption Index (WAI). At a raw material moisture content exceeding 12.5% there is no correlation between the content of brewer’s spent grain and WAI. Water Solubility Index (WSI) values decrease with an increasing content of brewer’s spent grain in the sample, irrespective of moisture content in the extruded mixture. An addition of BSG to extrudates makes it possible to obtain a product with a high content of dietary fibre, particularly cellulose and hemicellulose fractions. Extrudates produced from a raw material with a moisture content of 12.5% received the highest scores in sensory evaluation. At such a moisture content of the raw material an acceptable product with a 15% brewer’s spent grain content was obtained. Higher additions of BSG resulted in a reduced expansion, increased density and lower desirability of the product due to the specific aroma and after-taste of BSG.

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Changes of Acceptability of ‘Jonagold’ and ‘Gala’ Apples During Storage in Normal Atmosphere

Changes of Acceptability of ‘Jonagold’ and ‘Gala’ Apples During Storage in Normal Atmosphere

Proper development of storage marketing strategy for apples for fresh fruit market requires not only detailed information on dynamics of changes of objective quality indices during storage but also on their impact on consumer acceptability. The experiment was aimed at determination of ‘Jonagold’ and ‘Gala’ apple quality in relation to length of cold storage.

Apples were harvested at optimal stage of ripeness and their quality was estimated monthly starting from the day when fruit were picked up to 6 months of storage. Tests were made after cold storage at 0°C and after 7 days shelf-life at 18°C. Beside measurement of the most important parameters such as firmness, soluble solids, and acidity the studies covered measurements of changes of weight of single fruit, instrumental measurement of juiciness and sensory acceptability of texture and flavour made concurrently on laboratory scale and in semi-consumer tests (in a group of 40 respondents).

The largest decreases of firmness and juiciness were observed in the first and second month of storage. Changes of acidity and weight losses were proportional to storage period, while soluble solids changes were rather small and the direction depended on storage length. It was proved that the highest score for sensory acceptability received apples stored in cold room for one month. Slightly lower score obtained fruits tested directly after picking and after 2 months of storage. With extension of storage of fruit in the cold room sensory acceptability of both cultivars decreased when judged either by expert panel or by consumers.

According to the present fruit growers custom fruits of both cultivars after storage in normal atmosphere would be directed to retailers not earlier that at the end of December or beginning of January (i.e. after at least 3 months of storage), when their quality evidently decreases, and average consumer purchasing fruits in a store or at local market has no chance to esteem potential values of such popular cultivars as ‘Gala’ and ‘Jonagold’.

Open access
Sensory Quality of Carrots from Organic and Conventional Cultivation

Summary

The aim of the study was to determine the effect of the cultivation method (organic and conventional) on the sensory quality of carrot roots - fresh, stored, and cooked. The study was conducted in the sensory evaluation laboratory of the Institute of Horticulture in Skierniewice in 2009-2011. The carrot roots came from a certified experimental field with a stable ecosystem, adapted for conducting experiments on the organic growing of vegetables. At the same time, in the same soil and climatic conditions, carrots were grown in the conventional system. The experimental material consisted of two varieties of carrot - Perfekcja and Regulska. In a two-year cycle, sensory analyses were performed of fresh carrot roots, and of roots that had been stored and heat treated. The evaluations were conducted by a 10-person panel of specialists using the method of quantitative descriptive analysis (QDA). The results of qualitative sensory evaluations and the profilograms prepared on that basis for fresh and stored carrot roots indicated differences in the sensory characteristics between the tested varieties grown in organic and conventional systems. The greatest impact on the overall quality was exerted by the attributes: the carrot-taste, sweet taste, juiciness and hardness of the flesh. Organically grown carrots of the variety Regulska were characterized by the highest intensity of sweet taste and the carrot- taste, and by the best hardness, crunchiness, crispness and juiciness of the flesh. Fresh roots of this variety received the highest overall score. There were also some differences in the sensory characteristics of carrot roots after several months of storage, and then after cooking them, depending on the variety and cultivation method. In both years of the study, following the storage period, the cooked carrot roots of the variety Perfekcja from organic cultivation received the highest scores for overall quality. After storing and subjecting carrot roots to heat treatment, there was a significant decrease in the intensity of most of the quality descriptors, such as taste, smell and texture, when compared with the fresh roots under evaluation

Open access
Production and Evaluation of Soft Cheese Fortified with Ginger Extract as a Functional Dairy Food

Production and Evaluation of Soft Cheese Fortified with Ginger Extract as a Functional Dairy Food

Soft cheese fortified with ginger extract as a functional dairy food was evaluated. Buffalo's milk retentate was divided into three equal portions. One batch had no ginger extract as a control. The latter batches were fortified with extract at the rate of 1.5 or 3.0 g/kg. All batches were salted with 4% NaCl/water phase. The resultant cheese samples were divided into 2 parts; one was separately picked in salted permeate (4%), while the other was stored without pickling at 5±2°C for 6 weeks. The results revealed that cheese pickling increased the cheese proteolysis and lipolysis, and decreased pH and TVFAs. Fortification with ginger extract enhanced cheese proteolysis and TFVAs, while reduced pH value and oxidative rancidity of cheese. Physically, un-pickled soft cheese was more springy, harder, darker and more yellowish compared with pickled cheese samples. Ginger extract caused an increase in cohesiveness, whiteness and yellowish colour degree, and decrease in hardness of both pickled and un-pickled soft cheese. Ginger extract-fortified cheese enhances the growth of L. lactis ssp. lactis and L. lactis ssp. cremoris compared with control cheese. However, ginger extract exhibited the highest growth for Lactococcus strains in pickled cheese. Yeast and mould were detected only in cheese control sample after 2 weeks. Ginger extract-fortified cheese gained the highest scores for flavour, texture and overall acceptability in both pickled and un-pickled cheese, which became more acceptable to panelists than control cheese over storage.

Open access
Diprion pini L. (Hymenoptera, Symphyta, Diprionidae) population dynamics in the Low Dnieper region

Abstract

Pine sawflies (Hymenoptera, Symphyta, Diprionidae) are the most spread foliage browsing insects of pine forests in Europe, especially monovoltinous European pine sawfly Neodiprion sertifer (Geoffroy, 1785) and common pine sawfly Diprion pini (Linnaeus, 1758), which develops in one or two generations per year depending on weather. The outbreaks of both pine sawflies are the most frequent and intensive in the Steppe zone of Ukraine, especially in the Low Dnieper region, where pine forest (Pinus sylvestris Linnaeus and Pinus pallasiana D. Don) was planted on moving sands in the sixties of the 20th century. This research is aimed at the evaluation of the parameters for D. pini outbreak dynamics in the Low Dnieper region.

Outbreak severity, specific foci area and mean score of stand threat by D. pini were evaluated from the regional statistical reports. In the regional scale for 1979–2017, notable outbreaks of D. pini were registered in 1982, 1993, 2002, 2006 and 2017. An interval between maximums was from 4 to 11 years, in average 9 years. The growth of foci area in 1979–1998 as compared to 1999–2017 as well as correlation between pine stand area and annual area of this pest’s foci in different forests was not statistically significant. Graphical analysis of dynamics of D. pini focal area for 2010–2017 was done based on individual threat levels. Our study confirms the fact of three outbreaks for this period in three forest and hunting enterprises (FHE), two outbreaks in one FHE and one outbreak in one FHE. An interval between the outbreaks makes three or six years. The causes of such shortening of interval are discussed.

Open access
Ecosystem Functions of Steppe Landscapes Near Lake Baikal

Abstract

Recreational activity has a significant impact on the Priol’khonie steppes and forest steppes, which are part of the Pribaikalskyi National Park (western coast of Lake Baikal, Russia). The aim of this investigation is the assessment of different landscapes’ values for the provision of ecosystems functions and services. To meet these objectives, fieldwork was conducted in the Priol’khonie steppes and forest steppes during the summer of 2013. The function of phytomass formation was considered for different land-cover types identified in the area, and the above-ground phytomass and inter-rill erosion were measured. The level of landscape degradation was estimated and draft maps of phytomass stocks and vulnerability to soil erosion of the investigated area were compiled. To show the dependence between the studied ecosystem functions and the ecosystem services provided by them, a scoring of the latter was made. It was found that characteristics of ecosystem functions varied significantly in the steppes of the Priol’khonie.

Open access