دانلود رایگان مقاله لاتین خواص فیزیکوشیمیایی نشاسته ذرت از سایت الزویر
عنوان فارسی مقاله:
خواص فیزیکوشیمیایی و کریستالی هیدروترمال نشاسته ذرت استاندارد توسط عمل بخار دهی مستقیم
عنوان انگلیسی مقاله:
Physicochemical and crystalline properties of standard maize starch hydrothermally treated by direct steaming
سال انتشار : 2016
برای دانلود رایگان مقاله خواص فیزیکوشیمیایی نشاسته ذرت اینجا کلیک نمایید.
مقدمه انگلیسی مقاله:
1. Introduction
Starch which is a renewable biopolymer and one of the most abundant carbohydrates reserve, constitutes a fundamental material for food and non-food use due to its large physicochemical properties. Generally, modification of starch is carried out to enhance the positive characteristics and eliminate the shortcomings of native starches. Heat-Moisture Treatment (HMT) modifies the physicochemical properties of starch without destroying the granular structure. Starch is heated at high temperature ( < 140 ◦C) but with restricted moisture between 13 and 30 g/100 g (Arns et al., 2015;Kong et al., 2014; Sui et al., 2015 Zen, Ma, Kong, Gao, & Yu, 2015), above its glass transition temperature and below the gelatinization temperature for times of few minutes (Zarguili, Maache-Rezzoug, Loisel, & Doublier, 2006; Lim, Chang, & Chung, 2001) to hours (Ji et al., 2015; Kong et al., 2014 Wang, Zhang, Chen, & Li, 2016). The comprehension of starch phase transitions is extremely important in the food processing operations. Starch with ∗ Corresponding author. E-mail address: zrezzoug@univ-lr.fr (Z. Maache-Rezzoug). a semi-crystalline structure has two phase transitions which are likely to occur during HMT treatment: the glass transition that concerns the amorphous phase (mainly the branching regions of the amylopectin andmost of amylose chains) andmelting of crystallites (formed by adjacent short chains of amylopectin intertwined into double helices). The melting temperatures of crystallites depend strongly on the moisture content. For moisture content higher than 60% (w/w), only one single endotherm occurs over a constant temperature range, reflecting the loss of semi-crystalline order and transition temperature is referred to as gelatinization temperature. For lower moisture contents, multiple transitions occur that reflect melting and recrystallisation processes appearing simultaneously during heating (Biliaderis, Page, Maurice, & Juliano, 1986;MaacheRezzoug, Zarguili, Loisel, Queveau, & Buleıon, 2008 ´ ). The transition temperatures, designated as melting temperatures, increase and multiple endotherms are formed to the detriment of gelatinization endotherm. The melting term is then preferred to describe the thermal transitions during heating at low or intermediate moisture contents. In a previous work (Maache-Rezzoug et al., 2008), we have shown that the low moisture content (i.e. less than 35%) prevailing during DIC treatment were not sufficient to ensure that the gelatinisation happens. Many studies have been carried outon physicochemical properties of starch granules after HMT treatment. The properties of treated starches depend on the starch origin (Maache-Rezzoug, Zarguili, Loisel, & Doublier, 2010; Collado, & Corke, 1999; Gunaratne, & Hoover, 2002; Hoover and Manuel, 1996; Hoover and Vasanthan, 1994; Kulp, & Lorenz, 1981) and treatment conditionsused(Kong et al., 2014; Sui et al., 2015; Takaya and Nishinari, 2000). Some investigations (Chung, Liu, & Hoover, 2009; Gunaratne, & Hoover, 2002; Hoover & Manuel, 1996 Malumba, Massaux, Deroanne,Masimango, & Bera, 2009;Vermeylen, Goderis,Reynaers, & Delcour, 2006) have shown that the characteristic temperatures and enthalpy of gelatinization (H) of treated starches by HMT were mainly influenced by applied moisture level and temperature. Maache-Rezzoug, Zarguili, Loisel, Doublier, & Buléon (2011) observed similar effects after DIC treatment, except that the gelatinization temperature range was narrowed as observed with annealing (Hublin, 1994; Jayakody & Hoover, 2008). The authors suppose that the DIC treatment has led first the melting of crystallites of low cohesion,those requiring less energy and the remaining crystallites in the residual structure have greater cohesion. Bahrani, Loisel, Doublier, Rezzoug, & Maache-Rezzoug (2012) have already shown during the steaming of SMS by three HMT processes that the heating of starch granules is the result of transfer of latent heat of steam condensation by direct contact with saturated steam that also contributed to water transfer. Starch temperature rises from room temperature to steam equilibrium temperature. The higher the difference in temperature, the higher the quantity of condensed water, which causes increasing of starch moisture content (Zarguili et al., 2006). Direct Vapour-Heat Moisture Treatment, termed as DV-HMT treatment by our team, consists in heating up starch by saturated steam injected from atmospheric pressure up to processing steam pressure level. This treatment belongs to HMT according to the definition of Sair and Fetzer (1944). As regards to RP-HMT (Maruta et al., 1994) and DIC, the two processes begin by the setting up of vacuum prior to injection of saturated steam, contributing to intensify its diffusion into the product by reducing the air resistance. Consequently, the time required to reach steam equilibrium temperature is shortcut (Bahrani, Monteau, Rezzoug, Loisel, & Maache-Rezzoug, 2014). Only DIC process contains a final step of abrupt decompression which carries out towards the vacuum (Rezzoug, Maache-Rezzoug, Mazoyer, & Allaf, 2000) instead of atmospheric pressure as for DV-HMT and RP-HMT.When pressure suddenlydecreases,the autovaporization whichis anadiabatic transition occurs and water rashly escapes accompanied by a rapid cooling, whose value stabilizes at the equilibrium temperature of final pressure. The mechanical action and the intense shear of granules contribute to alter the crystalline structure; some mechanical energy is converted into internal energy (Huang, Lu, Li, & Tong, 2007). Bahrani et al. (2014) and Zarguili, Maache-Rezzoug, Loisel and Doublier (2009) showed during DV-HMT and RP-HMT/DIC processes that the treatments were homogeneous; the absence of moisture gradients between the different starch layers was evidenced during monitoring of spatial evolution of moisture content in the thickness direction at different processing times. The presence of initial vacuum in the case of RP-HMT/DIC, contributes to generate a more significant amount of condensed steam than for DV-HMT, the moisture content were 24 and 20%, respectively. For a same SP, the volume occupied by air in the reactor is replaced by an equivalent volume of steam. The objective of this study was to investigate the effect of three hydrothermal processes; DV-HMT RP-HMT and DIC on the physicochemical changes of SMS. The impact of processes, mainly the additional vacuum steps before and after steaming phase of starch granules, on the thermal transitions, structural characteristics and morphological properties were investigated at different processing temperatures.
برای دانلود رایگان مقاله خواص فیزیکوشیمیایی نشاسته ذرت اینجا کلیک نمایید.
کلمات کلیدی:
[PDF]Properties of corn starch subjected hydrothermal modification** agro.icm.edu.pl/agro/element/bwmeta1.element.agro...571d.../31-1-Gryszkin.pdf by A Gryszkin - 2017 Jun 1, 2016 - Properties of corn starch subjected hydrothermal modification**. Artur Gryszkin* ..... Mean values ± standard deviations are showed. Means in a ... Properties of corn starch subjected hydrothermal modification ... https://www.degruyter.com/view/j/intag.2017.31.issue-1/intag.../intag-2016-0031.xml by A Gryszkin - 2017 Feb 7, 2017 - Structural modifications and thermal transitions of standard maize starch after DIC hydrothermal treatment. Carbohyd. Polym., 74, 802-812. [PDF]Effect of hydrothermal treatment on the physical and rheological ... - Hal https://hal.archives-ouvertes.fr/hal-00413504/document by C Loisel - 2006 - Cited by 38 - Related articles Sep 4, 2009 - Keywords : Hydrothermal treatment, Maize starch, Pregelatinization, ... and functional properties of two native starches, standard maize starch ... [PDF]Influence of DIC hydrothermal process conditions on the ... - Hal https://hal.archives-ouvertes.fr/hal-00413508/document by I Zarguili - 2006 - Cited by 27 - Related articles Sep 4, 2009 - DIC hydrothermal process conditions on the gelatinization properties of standard maize starch. Journal of Food Engineering, Elsevier, 2006, ... Influence of DIC hydrothermal process conditions on the gelatinization ... agris.fao.org/agris-search/search.do?recordID=US201301086340 by I Zarguili - 2006 - Cited by 27 - Related articles Influence of DIC hydrothermal process conditions on the gelatinization properties of standard maize starch [2006]. Zarguili, I. Maache-Rezzoug, Z. Loisel, ... Effect of hydrothermal treatment on the physical and rheological ... agris.fao.org/agris-search/search.do?recordID=US201301042843 by C Loisel - 2006 - Cited by 38 - Related articles Effect of hydrothermal treatment on the physical and rheological properties of ... Standard maize (SMS) and waxy maize starch (WMS) were hydrothermally ...
