جستجوی مقالات مرتبط با کلیدواژه « مدل آرنیوس » در نشریات گروه « صنایع غذایی »

In order to the shelf-life prediction of white shrimp fillet (Litopenaeus vannamei) using Arrhenius mathematical model and Artificial Neural Network at different temperatures (-15, -25, -35, -45 °C), the qualitative changes of the fillet including salt extractable protein (SEP), K index, total volatile nitrogen bases (TVB-N), peroxide index (PV), barbituric acid (TBARS), electrical conductivity (EC) and sensory evaluation (SA) were investigated. For the Arrhenius model, the relative error range between the measured and predicted values for the quality factors i.e. TVB-N, SA, EC, TBRAS, K and SEP was -73.17-15.12, -2.54-13.04, -6.47-1.62, -0.81-0.00, -25.99-2.02, -5.59-0.82%, respectively. Regarding to Artificial Neural Network model, the relative error range between the predicted and measured values for the quality factors TVB-N, SA, EC, TBRAS, K and SEP were 0.00, 0.00, -0.38-0.00, 0.00, 0.00 and -0.08-0.03%, respectively. The MSE values of the Artificial Neural Network model were lower than the Arrhenius model in most of the qualitative factors. The R2 of the frozen shrimp quality factors of the Artificial Neural Network model was higher than the Arrhenius model, except for the SA factor. The artificial neural network model was able to better show the trend of changes in the quality of shrimp stored during the 6 months of the freezing period, at of -15 to -45 °C, compared to the Arrhenius model.

Hawthorn (Crataegus pinnatifida), belonging to the Rosaceae family, consists of small trees and shrubs. The color of the ripe fruit varied from yellow, through green to red and on to dark purple. Most of the species ripen their fruit in early to mid-autumn. Beneficial effects of hawthorn fruit extracts have been confirmed by various studies. Pharmacological data showed that hawthorn fruit and its preparations enhance myocardial contraction and conductivity, protect against ischemia. They have a sedative action, a protective effect against arrhythmia and increase of coronary vessel flow. They have also positive effects on the cardiovascular system. Hawthorn is one of the most widely consumed horticultural products, either in fresh or processed form. It is also an important component of many processed food products because of its excellent flavor, attractive color and high content of many macro- and micro-nutrients. Uncertain storage conditions lead to considerable quality loss in hawthorn fruits, which affect their consumer acceptability. Properties such as color, firmness and moisture provide valuable information for the monitoring of quality changes in postharvest fruits because of their reliability and rapid and easy measurement. These changes are consequences of many biochemical and physiological processes that occur during fruit ripening, such as respiration and transpiration. In addition, these changes depend on the external conditions to which the fruit is exposed. To estimate changes in fruit quality as a function of storage conditions, the evolution of certain quality-indicative properties such as color, firmness or weight can be used to provide related information on the quality grade of the product stored. Kinetic models can be used as tools to describe quantitative physicochemical changes in foods during processing. Kinetic models can be linear or non-linear forms of rate law equations. The rate process of food constituents is usually defined by zero, first or second order kinetics.

In this study, changes in physicochemical characteristics associated with fruit quality were investigated during various hawthorn fruit storage conditions include: cold (1ºC and RH=90%), refrigerator (10 ºC and RH=85%) and room conditions (25 ºC and RH=60%). Color quality parameters (L*, a*, b*, C*, h* and ΔE), geometrical parameters, weight loss, firmness, total soluble solid (TSS), pH, titratable acidity (TA) and ripening index (RPI) were the measured factors. Different mathematical models were successfully proposed and adjusted to represent the change in physicochemical properties as a function of storage temperature. Among various kinetics model, five models (Zero-order, First-order, Second-order, Fractional conversion and Weibull models) were fitted to experimental data and model parameters in equations were determined by multiple regression analysis.

Storage of hawthorn fruits at different temperature affected their color (L*, a*, b*, C*, h* and ΔE), geometrical, physical (weight loss, firmness) and chemical properties (TSS, pH, TA and RPI). Storage at all conditions had significant impact on the physicochemical parameters analyzed (except some geometrical characteristics). Significant alterations in hawthorn color, firmness and weight loss were observed. The firmness, titratable acidity, pH, ripening index, color characteristics (except a* and C*) decreased while weight loss, total soluble solid, a* and C* increased significantly (p<0.05). Hawthorn stored at low temperatures revealed a delay on quality reduction reactions in terms of color, firmness and weight loss. The results indicated that the First-order and Weibull kinetic models provided the best prediction of the changes in physicochemical parameters. The storage temperature effect was successfully described by the Arrhenius law. Understanding the mechanisms in which these conditions affect the quality changes processes is of great importance because it allows their appropriate modification to maintain quality and maximize storage time. The outcomes of this study provide additional and useful information for hawthorn fruits under various storage conditions.

Honey is a natural food product having a high nutritional and medicinal value. It is a sweet, viscous substance produced by the honeybees from the nectar of plants. Sensory and physical properties and chemical composition of honey depend on the botanical origin and the regional and climatic conditions of the area in which it is produced.The knowledge of honey rheology is very important for its processing, quality control, process control, and selection of proper process equipment, storage, handling, and transportation and plays an important role in fluid heat transfer. Rheological properties of honeys depend on many factors including composition, temperature, and amount and size of crystals. Different kinds of honeys with various floral origins (such as Rosa, Thyme, Astragalus, Trifolium, sunflower, Medicago, alfalfa and etc.) are produced in different regions of Iran. In this study, some physicochemical and rheological properties of four Iranian honeys from Golestanprovienceobtained from various floral sources, two poly floral (Mountain, Forest) and two mono floral (Sunflower, Ivy) were compared with adulteratedand sugar honeys.

Sixhoney samples were collected directly from beekeepers in Golestan Province,two monofloral (Sunflower, Ivy) and two polyfloral(Mountain, Forest), adulterated and sugar honeys. Some physico–chemical characteristics of samples including water content, Hydroxymethylfurfural content (HMF), diastase activity, pH, ash, free acidity, reducing sugars (fructose and glucose), sucrose contentand electrical conductivity were determined by the harmonized methods of the International Honey Commission. The rheological measurements were also carried out on the honey samples at eighteen rotations, ranging from 5-200 rpm and at five temperatures, ranging from 10-30ºC, using a viscosimeter Brookfield.

The samples were found to be different from each other in terms of physico-chemical properties. In the natural honey samples, this discrepancy can be due to diversity in original plant and harvesting season. All the values obtained in the natural honey samples were agreement with those reported by Codex Alimentarius and ISIRI. The values of sucrose and fructose/glucose ratio the sugar honey sample and sucrose, fructose/glucose ratio, pH, HMF, diastase activity of adulterated honey were not in the range suggested by Codex Alimentarius and ISIRI.

Rheological characteristics of honeys were evaluated at different temperatures (10, 15, 20, 25 and 30ºC). All the honeys exhibited Newtonian behavior for shear rate in range of 1.045- 41.8 s-1.The temperature dependence of viscosity was described using the Arrhenius and the Vogel–Taumman–Fulcher (VTF) equations.Two models (Power Law and Exponential models) were also investigated to describe the concentration (ºBrix) dependence of viscosity.

Iranian date is unique among a few date producing countries and is accepted as one of the exportable products. By removing kernel from soft dates and following extrusion a semi solid product namely date paste can be produced. This product can be used as a sugar substitute in many food formulations. Rheological properties and fluidity are some of its main physicochemical properties. These properties are useful in product development, quality control, design process, shelf life prediction, packaging and product preservation. The aim of this research is determining rheological properties of date paste produced in our country.