Development of biodegradable coatings for covered horizontal bunker‐stored silage

Abstract

The addition of different plasticizers, thickeners and hydrophobic compounds such as fatty acids in biodegradable coatings has been evaluated using pH values and dry matter content as criteria in silage during one month of storage at room temperature under laboratory conditions. A base coating solution was prepared with whey protein concentrate, calcium caseinate and carboxymethylcellulose. From the base coating solution, derivative coating solutions were developed to evaluate the effect of plasticizers by incorporating glycerol at different concentrations and different ratios of sorbitol and glycerol. Thickening agents were also evaluated by adding fine silage powder, coarse silage powder, hay powder, or cornstarch. Derivative coating solutions were studied to evaluate the effect of fat constituents. Canola oil, beef fat, shortening, bees wax or candellila wax were added to the base solution following various procedures. Results showed that the addition of glycerol (320 g kg −1 ) in the coating formulation resulted in a pH value of 5.21 after 31 days of storage without visible spoilage under the coating. The presence of plasticizer compounds avoids the appearance of cracking in the coating during the early stage of conservation. The pH of silage coated with formulations containing coarse or fine silage powder was preserved below 5 until day 17 as compared to the other formulations where the pH was preserved below 5 only for 10 days. The incorporation of beef fat in the coating formulation resulted in the lowest pH as compared to all the other fat compounds evaluated, showing a value of 4.61 at the end of storage. The addition of glycerol, coarse silage and beef fat in the same coating formulation recovered by a hydrophobic layer of zein stabilized the pH to 4.47 for 28 days of storage with a final dry matter content at 344.3 g kg −1 without visible spoilage under the coating during all of the storage at room temperature.

Productivity, milk composition and milk quality of cows fed maize silage covered with oxobiodegradable film

“…Self-heating of silages in silos may suggest that the biodegradable layer failed to protect the silages from spoilage when they were exposed to atmospheric influences. Denoncourt et al (2004b) reported that production of good silage using biodegradable film is dependent on plastic components. In fact, a number of components characterized by different mechanical and physical properties give specific functional properties to the film.…”

“…However, the management of worn-out polyethylene films is a problem. Alarmingly, worn-out silage wrap is going to illegal dumping sites, being buried or burned, while the released components of polymer plastics are a serious environmental threat (Rymarz and Klecan, 2001;Majdiuk, 2002;Rutkowska et al, 2002;Denoncourt et al, 2004aDenoncourt et al, , 2004bŚwiątkowski and Walczak, 2004;Borreani and Tabacco, 2005;Laffin et al, 2005;Denoncourt et al, 2006Denoncourt et al, , 2007Borreani et al, 2014;Borreani and Tabacco, 2015). One alternative to standard coating is biodegradable film produced on the basis of natural origin polymers (chitosan, cellulose, starch, soy or whey protein, and others) or synthetic macromolecular compounds that provide food for microorganisms.…”

“…One alternative to standard coating is biodegradable film produced on the basis of natural origin polymers (chitosan, cellulose, starch, soy or whey protein, and others) or synthetic macromolecular compounds that provide food for microorganisms. The use of biodegradable materials for silage making is conditional on efficient protection of ensiled material from oxygen and on maintaining the high nutritive value of the feeds at feeding (Świątkowski and Walczak, 2004;Denoncourt et al, 2004aDenoncourt et al, , 2004bDenoncourt et al, , 2006Denoncourt et al, , 2007.…”