Влияние на генотипа и срока на съхранение върху параметрите на текстурата в картофени клубени

Potato lines bred by intraspecific hybridization of Solanum tuberosum L. were evaluated on their textural properties in two consecutive years. The plants were grown under mountain conditions at 1610 m altitude and were harvested at the end of September. The cutting test was performed using a Warner-Bratzler blade of texture analyzer (TA) for obtaining the maximum force to shear the tubers. Textural parameters were analysed right after harvesting, 3- and 6-month storage under ambient conditions (2-8 ºC and 70-90% Rh) in unheated storehouse. It was found out that the values of all investigated physical parameters decreased during the storage. Higher influence of the storage duration than the genotype was recorded on the dynamic of yield force, modulus of deformation, deformation work and rupture force. Based on the studied physical qualities line E 1096 was selected as the most appropriate for long-term storage because of the slightest softening of the tubers and the most homogenous parameters of the texture at the end of the storage. The observed correlations indicated that the yield force may give the best information about the quality of raw potato texture.В две последователни години са оценени параметрите на текстурата на линии картофи (Solanum tuberosum L.), създадени чрез вътревидова хибридизация. Растенията са отгледани при планински условия на 1610 метра надморска височина и са реколтирани в края на месец септември. Тестът за разрязване е проведен с текстурен анализатор (TA) с помощта на нож Warner-Bratzler за получаване на максимална сила за срязване на клубените. Анализът е извършен непосредствено след реколтиране, след три и шестмесечно съхранение в условията на неотопляемо складово помещение при температурен диапазон 2-8 ºC и 70-90% относителна влажност на въздуха. Установено е, че продължителността на съхранение оказва по-голямо влияние върху динамичната сила на поддаване, модула на деформация, работата за деформация и силата на разрушаване в сравнение с генотипа. Стойностите на всички изследвани физични параметри намаляват по време на съхранението. Линия Е 1096 е най-подходяща за дългосрочно съхранение поради най-слабото омекване на клубените и най-хомогенни стойности на параметрите на текстурата в края на съхранението. Въз основа на наблюдаваните корелации може да се заключи, че силата на поддаване би могла да даде най-добра информация за качеството на текстурата на непреработените картофи

Investigation of edible coatings on the physical, chemical and microbiological characteristics of processed melons during storage

The possible use of chitosan coating on fresh-cut melons (Cucumis melo var. Cantalupensis) was investigated in this research topic. Manually sliced melons were treated with solutions of 10 g/kg chitosan and 10 g/kg chitosan with calcium lactate and then stored at 4°C for 8 days. Physical, physicochemical, microbiological and sensory properties of the samples were monitored during the storage period. It was found that chitosan coatings inhibited the growth of microorganisms and affected significantly and positively the storage time of the products. Changes in the sensory qualities of taste were evaluated. A chitosan coating retarded water loss and the drop in sensory quality, increasing the soluble solid content and titratable acidity. The data revealed that applying a chitosan coating preserved effectively the quality and extended the shelf life of fresh-cut melons

Effect of ripening temperature on the texture of cow milk Kashkaval cheese

Texture development during ripening of cow milk Kashkaval cheese at different temperatures (9±1 °С, 11±1 °С and 13±1 °С) was studied. Texture parameters representing cheese hardness, cohesiveness, springiness, adhesiveness, gumminess and chewiness were determined by texture profile analysis. It was found that hardness, gumminess and adhesiveness of all studied samples increased, while springiness and cohesiveness decreased during ripening. An increase of chewiness values during the first stages of ripening was observed, followed by a decrease to the 60th day. It was found that ripening time, as well as ripening temperature had a significant effect on the changes in Kashakaval texture parameters. Cheese samples ripened at higher temperatures had lower values for hardness, cohesiveness, gumminess and chewiness. Ripening temperature had no significant effect on the changes in springiness and adhesiveness of the studied samples. The results obtained showed that by an appropriate combination of the two factors, ripening time and temperature, the changes in the Kashkaval cheese texture can be controlled, which is important for the quality of the final product

Enhancing postharvest quality of fresh-cut plums with chitosan-grape seed oil edible coatings

Edible coatings are traditionally used to improve food appearance and conservation due to their environmentally friendly nature. In this study fresh cut (halved and pitted) plum (var. Stanley) fruits were coated by chitosan grape-seed-oil (GsO) nanoemulsion. Physical, physico-chemical, microbiological and sensorial properties were examined 3 times during 9 d refrigeration storage. The control probes wasted their safety and quality after the 4th d. The coated probes preserved their quality and safety to the end of the storage period. The fruits with chitosan coating showed smaller microbiological contamination but the chitosan GsO coated fruits showed higher values in the sensorial parameters. The coated samples preserved their sensorial parameters up to 80% on the 9th d

Postharvest quality and safety of fresh-cut melon fruits coated with water soluble chitosan films

The research presents the effect of novel edible coatings based on low molecular weight chitosan on some properties of fresh-cut melon fruits – weight loss, total soluble solids, total acidity, mechanical strength and bacteria growth. Three different compositions were used as coatings – pure chitosan, chitosan and Ca lactate and alginate/chitosan multilayers. It was shown that the additional alginate layer substantially improves the protective properties of pure chitosan coating, resulting in preservation of cell structure. Negligible negative effect on the antibacterial activity of pure chitosan is demonstrated

An Osmotic Model of the Growing Pollen Tube

Pollen tube growth is central to the sexual reproduction of plants and is a longstanding model for cellular tip growth. For rapid tip growth, cell wall deposition and hardening must balance the rate of osmotic water uptake, and this involves the control of turgor pressure. Pressure contributes directly to both the driving force for water entry and tip expansion causing thinning of wall material. Understanding tip growth requires an analysis of the coordination of these processes and their regulation. Here we develop a quantitative physiological model which includes water entry by osmosis, the incorporation of cell wall material and the spreading of that material as a film at the tip. Parameters of the model have been determined from the literature and from measurements, by light, confocal and electron microscopy, together with results from experiments made on dye entry and plasmolysis in Lilium longiflorum. The model yields values of variables such as osmotic and turgor pressure, growth rates and wall thickness. The model and its predictive capacity were tested by comparing programmed simulations with experimental observations following perturbations of the growth medium. The model explains the role of turgor pressure and its observed constancy during oscillations; the stability of wall thickness under different conditions, without which the cell would burst; and some surprising properties such as the need for restricting osmotic permeability to a constant area near the tip, which was experimentally confirmed. To achieve both constancy of pressure and wall thickness under the range of conditions observed in steady-state growth the model reveals the need for a sensor that detects the driving potential for water entry and controls the deposition rate of wall material at the tip