پديد آورندگان :
محسن، زندي دانشگاه زنجان - دانشكده كشاورزي - گروه علوم و مهندسي صنايع غذايي , علي, گنجلو دانشگاه زنجان - دانشكده كشاورزي - گروه علوم و مهندسي صنايع غذايي , ماندانا، بي مكر دانشگاه زنجان - دانشكده كشاورزي - گروه علوم و مهندسي صنايع غذايي
كليدواژه :
زالزالك , شرايط نگهداري , مدل‌سازي سينتيكي , مدل آرنيوس , خصوصيات فيزيكي و شيميايي
چكيده لاتين :
Introduction: 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 micronutrients.
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.
Method and material: 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.
Result and discussion: 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.
