Physical and bioactive properties of corn starch – Buttermilk edible films

Abstract

39Nowadays, the accumulation of non-biodegradable plastics is a paramount environmental 40 concern which still has not been efficiently addressed (Azeredo, 2009). Bioplastics produced from 41 renewable resources are being recognized as a solution to environmental problems concerning waste 42and dependence on fossil fuels (Byun & Kim, 2014). Starch is one of the most widely used and 43promising materials in the bioplastics market due to its biodegradability, availability, renewability and 44 low cost (Wilhelm et al., 2003; Barnett, 2011). Native starch does not have thermoplastic properties; 45 however, with the addition of plasticizers and thermal-shearing processing, native starch gelatinizes 46and turns into thermoplastic starch (TPS), from which films can be obtained by using both solution 47 casting or thermoprocessing (Zhang et al., 2014). 48Biodegradable packaging materials can additionally be carriers of antioxidant and/or 49 antimicrobial agents (Sánchez-García et al., 2008) in order to obtain active packaging products, in 50 which active compounds are released into the food or the surrounding environment (e.g. head space) 51in the package so as to extend the shelf life of food and to improve its safety and quality properties 52 (Realini & Marcos, 2014). 53Oxidation is a chemical process, slower than microbial spoilage, which lies in a primary quality antimicrobials (Gyawali & Ibrahim, 2014;Moreira et al., 2005). 71Lactoferrin and lysozyme could be used for the purposes of conferring active properties to 72 biodegradable films (Jenssen and Hancock, 2009 (Arnold et al., 1977;Reyes et al., 2005). The bactericidal effect has been 79 attributed to its direct interaction with the bacterial membranes (García-Montoya et al., 2012). 80Specifically, LF has the ability to damage the outer membrane of Gram-negative bacteria directly due 81to its interaction with lipolisacharide (LPS) (Ellison et al., 1988). The use of Lysozyme (LZ) in 82antimicrobial packaging applications has been described by several authors (Barbiroli et al., 2012; 83 Gemili et al., 2009, Buonocore et al., 2005 PS was dispersed in distilled water at 2% wt., using magnetic stirring for 5 to 10 minutes. These 127PS dispersions were heated in a thermostatic bath at 99ºC for 30 minutes and stirred every 5 minutes. 128After cooling down with running water, glycerol was added (mass ratio of glycerol to PS was 0.25:1). 129The dispersions were homogenized with a rotor stator ultraturrax D125 for 4 minutes at 13,500 rpm, 137Teflon plates (150mm diameter) were used for film casting. The mass of film forming 138 dispersions corresponding to 1.5 g of solids was cast on each plate. After drying for 48 h at 45 %RH 139and 25ºC, the films were separated from the plates. For the purposes of studying the effect of storage 140 time on the physical properties of the films, the samples were stored, at 25ºC, for 1 or 5 weeks prior to 141analyses in desiccators at 54% RH, by using an oversaturated Mg(NO3)2 solution. In order to assess 142 the role of moisture cont...

Effect of Plasticizer Type and Concentration on Tensile, Thermal and Barrier Properties of Biodegradable Films Based on Sugar Palm (Arenga pinnata) Starch

“…Thus, starch has attracted a great deal of interest as a potential alternative to conventional plastics for packaging applications. Several studies have investigated the development and characterization of starch based films from corn [4,[6][7][8], potato [9][10][11][12][13], cassava [14][15][16][17][18][19][20], banana [21], yam [22,23], pea [1], sago [24][25][26], rice [27][28][29][30], maize [31][32][33][34], Kudzu [35] and agar [36][37][38][39]. According to Sahari et al [40] sugar palm starch is also a potential biopolymer material for making biodegradable films.…”

Influence of the processing method and antimicrobial agents on properties of starch‐gelatin biodegradable films

“…Starch and gelatin are biodegradable materials, widely available, of low cost and with very good film forming ability . The combination of thermoplastic starch with other polymers, such as gelatin, has been highlighted as a way of enhancing film mechanical behaviour, leading to films with higher resistance and elongation capacity .…”

Current knowledge of buttermilk: Composition, applications in the food industry, nutritional and beneficial health characteristics

“…In spite of its high protein content, with potential antioxidant or antimicrobial properties, buttermilk was not suitable for the formulation of starch film because of the undesirable effects of the other solids existing in the commercial powder on the properties of the film (Moreno et al . ).…”