تاثیر نوع نشاسته و مقدار گلیسرول بر خواص کششی و جذب رطوبت فیلم نشاسته های گرمانرم تهیه شده به روش اختلاط مذاب

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکترا،دانشکده کشاورزی، دانشگاه فردوسی مشهد

2 استاد، گروه علوم و صنایع غذایى، دانشکده کشاورزی، دانشگاه فردوسی مشهد

3 دانشیار، پژوهشکده فرایند پلیمرها، پژوهشگاه پلیمر و پتروشیمی ایران

4 دانشیار، گروه علوم و صنایع غذایى، دانشکده کشاورزی، دانشگاه فردوسی مشهد

چکیده

در این تحقیق، فیلم‌های انواع نشاسته گرمانرم به روش اختلاط مذاب تهیه شدند و تاثیر نوع نشاسته (گندم، ذرت و سیب زمینی) و مقدار نرم‌کننده گلیسرول بر خواص‌کششی و جذب رطوبت آن‌ها مورد بررسی قرار گرفت. نتایج بدست آمده نشان داد که با افزایش درصد وزنی گلیسرول از 25 به 40 برای نشاسته‌های گرمانرم گندم، ذرت و سیب‌زمینی، میانگین مقادیر مقاومت‌کششی فیلم مشروط‌شده آن‌ها در رطوبت نسبی 53% و دمای °C 25 به مدت 48 ساعت، به ترتیب از 3، 7/3 و 4/4 مگاپاسکال به 5/0، 1/1 و 4/1 مگاپاسکال و میانگین مقادیر مدول‌الاستیک به ترتیب از 25، 4/32 و 3/38 مگاپاسکال به 1، 5/1 و 9/2 مگاپاسکال کاهش یافت. همچنین با افزایش درصد وزنی گلیسرول از 25 تا 30 برای نشاسته‌های گرمانرم گندم، ذرت و سیب‌زمینی، میانگین مقادیر درصد افزایش طول تا نقطه پارگی فیلم آن‌ها به ترتیب از 5/20 ، 3/18 و 3/31 به 5/91 ، 7/72 و 3/50 افزایش و سپس با افزایش از 30 تا 40 به ترتیب به 3/37 ، 5/34 و 6/31 کاهش یافت. همچنین افزایش درصد وزنی گلیسرول موجب افزایش مقدار جذب رطوبت فیلم‌های هر3 نوع نشاسته گرمانرم شد، بطوری که با افزایش درصد وزنی گلیسرول از 25 به 35، میانگین مقادیر جذب رطوبت فیلم‌های نشاسته گرمانرم گندم، ذرت و سیب-زمینی نگهداری شده در رطوبت نسبی84% به مدت 7 روز به ترتیب از 8/26، 9/29 و 8/36 به 8/30، 6/34 و 7/41 افزایش یافت. داده‌های منحنی‌های همدمای جذب رطوبت تعادلی برای فیلم‌های3 نوع نشاسته گرمانرم توسط مدل پلگ مدل‌سازی شدند که ضرایب همبستگی بدست آمده بیانگر مناسب بودن مدل مذکور برای پیش‌بینی تغییرات مقدار جذب رطوبت فیلم-ها با رطوبت نسبی محیط بودند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The effect of starch type and glycerol content on tensile and moisture sorption properties of melt mixing prepared thermoplastic starch films

نویسندگان [English]

  • Mohammad Reza Abdollahi Moghaddam 1
  • Seyed Mohammad Ali Razavi 2
  • Yousef Jahani 3
  • Naser Sedaghat 4
1 PhD student, Department of Food Science & Technology, Ferdowsi University of Mashhad, Iran
2 Professor, Department of Food Science & Technology, Ferdowsi University of Mashhad, Iran
3 Associate Professor, Department of Plastics, Faculty of Polymer Processing, Iranian Polymer & Petrochemical Institute, Iran
4 Associate Professor, Department of Food Science & Technology, Ferdowsi University of Mashhad, Iran
چکیده [English]

In this research, wheat, corn and potato thermoplastic starch films were prepared through melt mixing method and the effect of starch type and glycerol plasticizer content on their tensile and moisture sorption properties was investigated. The results depicted that by increasing glycerol content at studied range, the tensile strength and elastic modulus of film of all three starch types decreased significantly, while their percentage of elongation at break first raised up to certain amount and then followed a decreasing trend. Also among three thermoplastic starches, potato thermoplastic starch films had the highest tensile strength and elastic modulus and the lowest percentage of elongation at break values due to having higher amount of amylopectin content than other two thermoplastic starches. For all of three thermoplastic starches, increasing glycerol content increased moisture absorption of films so that by increasing glycerol weight percentage from 25 to 35 , the moisture absorption of wheat, corn and potato thermoplastic starch films conditioned at relative humidity of 84% for 7days, increased from 26.8, 29.9 and 36.8 to 30.8, 34.6 and 41.7 respectively. Indeed at the same environment relative humidity and glycerol content, the potato thermoplastic starch films had higher moisture absorption than wheat and corn thermoplastic starch films. The data of moisture sorption isotherm curves for the three thermoplastic starch films was modeled by Peleg model. The obtained correlation coefficients explained the suitability of this model for prediction of changes of moisture absorption of films versus water activity.

کلیدواژه‌ها [English]

  • Starch
  • Glycerol
  • Tensile Properties
  • Moisture Absorption
  • Thermoplastic
  • Film
[1] Thomas, D., Atwell, A. (1999). Starches , Eagan Press , St. Paul., 48-65.

[2] Swinkels B. J. J. M. (1985). Composition and Properties of Commercial Native Starches. Starch-Stärke, 37, 1–5.

[3] Willett, J. (1994). Mechanical properties of LDPE/granular starch composites. J Appl Polym Sci.,  54, 1685–1695.

[4] Roy, S.B., Ramaraj, B., Shit S.C., Nayak S.K. (2011). Polypropylene and potato starch biocomposites: Physicochemical and thermal properties. J Appl Polym Sci., 120, 3078–3086.

[5] Sin, L. T., Rahman, W. A.W. A., Rahmat, A. R., Mokhtar, M. (2011). Determination of thermal stability and activation energy of polyvinyl alcohol–cassava starch blends. Carbohydrate Polymers, 83, 303–305.

[6] Jacobsen, S., Fritz, H. G. (1996). Filling of poly (lactic acid) with native starch.  Polym Eng Sci., 36, 2799–2804.

[7] Lu, D. R., Xiao, C.M., Xu, S. J. (2009). Starch-based completely biodegradable polymer materials. Express Polymer Letters, 3, 6 , 366–375.

[8] Yu, L., Dean, K., Li, L. (2006). Polymer blends and composites from renewable resources. Prog. Polym. Sci., 31 , 576–602.

[9] Huneault, M.A., Li,  H. (2007). Morphology and properties of compatibilized polylactide/thermoplastic starch blends. Polymer, 48, 270-280.

[10] Ren, J., Fu, H., Ren, T., Yuan, W. (2009). Preparation, characterization and properties of binary and ternary blends with thermoplastic starch, poly (lactic acid) and poly (butylene adipate-co-terephthalate). Carbohydrate Polymers, 77, 576–582.

[11] Lourdin, D., Bizot, H., Colonna, P. (1996). "Antiplasticization" in Starch-Glycerol films? J Appl Polym Sci., 63, 1047-1053.

[12] Ave´rous, L.,  Moro, L.,  Dole, P.,  Fringant, C. (2000). Properties of  thermoplastics blends:

starch–polycaprolactone. Polymer, 41 (11), 4157–4167.

[13] Zhang, Y., Han, J.H. (2006). Mechanical and thermal characteristics of pea starch films plasticized with

monosaccharides and polyols.  J. Food Sci. 71, 109-118.

[14] Mikus, P.Y., Alix, S., Soulestin, J., Lacrampe, M. F., Krawczak, P., Coqueret, X., Dole, P. (2014). Deformation mechanisms of plasticized starch materials. Carbohydrate  Polymers, 114, 450–457.

[15] Ave´rous, L., Fringant, C. (2011). Association between plasticized starch and polyesters: processing

and performances of injected biodegradable systems. Polym. Eng. Sci., 41 (5), 727–734.

[16] Dai, H., Chang, P.R., Geng, F., Yu, J., Ma, X. (2010).  Preparation and properties of starch-based film using N,N-bis(2-hydroxyethyl)formamide as a new plasticizer. Carbohydrate  Polymers, 79, 306-311.

[17] Lourdin, D., Coignard,L., Bizot, H., Colonna, P. (1997). Influence of equilibrium relative humidity

and plasticizer concentration on the water content and glass transition of starch materials. Polymer, 38(21), 5401-5406.

[18] Shi, R., Liu, Q., Ding, T., Han, Y., Zhang, L., Chen, D., Tian, W. (2007). Ageing of Soft Thermoplastic Starch with High Glycerol Content. J Appl Polym Sci., 103, 574–586.

[19] Forssell, P.M., Mikkila, J.M., Moates, G.K., Parker, R. (1997). Phase and glass transition behaviour, of

concentrated barley starch-glycerol-water mixtures, a model for thermoplastic starch. Carbohydrate Polymers, 34 , 275-282.

[20] Graaf de, R.A., Karman A.P., Janssen L.P.B.M. (2003). Material properties and glass transition temperatures of differential thermoplastic starches after extrusion processing. Starch, 55, 80-86.

[21]Swinkels, J. J. M. (1985). Composition and properties of commercial native starches. Starch, 37, 1–5.

[22] Hulleman, S.H.D., Janssen, F.H.P., Fell, H. (1998).  The role of water during plasticization of native

starches. Polymer, 39(10), 2043-2048.

 [23] Mitrus, M., Moscicki, L. (2009). Physical properties of thermoplastic starches. Int. Agrophysics, 23, 305-308.

[24] ASTM. (2002). Standard test method for tensile properties of thin plastic sheeting. In standards designations: D882 - 02. Annual book of ASTM. Philadelphia, Pa: American society for testing and materials.

[25] Yu, J., Gao, J., Lin, T. (1996). Biodegradable thermoplastic starch. J Appl Polym Sci., 62 , 1491-1494.

[26] Yu, J., Chen, S., Gao, J., Zheng, H., Zhang, J.,  Lin, T. (1998). A study on the properties of starch/glycerine blend. Starch ,50 , 246.

[27] Chang, Y.P., Karim, A.A., Seow, C.C. (2006). Interactive plasticizing–antiplasticizing effects of water and glycerol on the tensile properties of tapioca starch films. Food Hydrocoll., 20, 1–8.

[28] Sanyang, M.L., Sapuan , S.M., Jawaid , M., Ishak , M.R., Sahari, J. (2015). Effect of Plasticizer Type and Concentration on Tensile, Thermal and Barrier Properties of  Biodegradable Films Based on Sugar Palm (Arenga pinnata) Starch. Polymers,  7, 1106-1124.

[29] Zullo, R., Iannace, S. (2009). The effects of different starch sources and plasticizers on film blowing

of thermoplastic starch: Correlation among  process, elongational properties and macromolecular structure.

Carbohydrate Polymers, 77 , 376–383.

[30] Liu, P., Gu, C., Zeng, Q. (2012). The Thermal and Rheological Properties of Starch Plasticized in

Glycerol-Water Mixture. Advanced Materials Research, 343, 38-42.

[31] Godbillot, L., Dole, P., Joly, C., Roge, B., Mathlouthi, M. (2006). Analysis of water binding in starch plasticized films. Food Chemistry, 96 , 380–386.

[32] Enrion, J.I., Hill, S.E., Mitchell, J. R. (2007). Sorption behavior of mixtures of glycerol and starch. J. Agric. Food Chem.,  22, 2956–2963.

[33] Suppakul, P., Chalernsook, B., Ratisuthawat, B., Prapasitthi, S., Munchukangwan, N. (2013). Empirical modeling of moisture sorption characteristics and mechanical and barrier properties of cassava flour film and their relation to plasticizing-antiplasticizing effects. LWT Food Sci. Technol., 50 , 290-297.

[34] Peleg, M. (1993). Assessment of a semi-empirical four-parameter general model for sigmoid moisture sorption isotherms. J. Food Process. Eng., 16, 21-37.

[35] Coupland, J.N., Shaw, N.B., Monahan, F.J., O’Riordan, E.D., O’Sullivan, M. (2000). Modeling the effect of glycerol on the moisture sorption behavior of whey protein edible films. J. Food Eng., 43, 25-30.