Baldev Raj

Structure–property relation in low-density polyethylene–starch immiscible blends

The effect of starch content, on the physico-mechanical properties viz., density, tensile strength and percentage elongation and optical properties like percentage transmittance at different wavelengths of low-density polyethylene/starch blended films has been investigated. The changes have been interpreted quantitatively in terms of microcrystalline parameters compiled using wide angle X-ray scattering data.

Production and characterization of bacterial polyhydroxyalkanoate copolymers and evaluation of their blends by fourier transform infrared spectroscopy and scanning electron microscopy.

Rhizobium meliloti produced a copolymer of short chain length polyhydroxyalkanoate (scl-PHA) on sucrose and rice bran oil as carbon substrates. Recombinant Escherichia coli (JC7623ABC1J4), bearing PHA synthesis genes, was used to synthesize short chain length-co-medium chain length PHA (scl-co-mcl-PHA) on glucose and decanoic acid. Fourier transform infrared spectroscopy (FTIR) spectra of the PHAs indicated strong characteristic bands at 1282, 1723, and 2934 cm−1 for scl-PHA and at 2933 and 2976 cm−1 for scl-co-mcl-PHA polymer. Differentiation of polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-hydroxyvalerate-P(HB-co-HV) copolymer was obseverd using FTIR, with absorption bands at 1723 and 1281 for PHB, and at 1738, 1134, 1215 cm−1 for HV-copolymer. The copolymers were analyzed by GC and 1H NMR spectroscopy. Films of polymer blends of PHA produced by R. meliloti and recombinant E. coli were prepared using glycerol, polyethylene glycol, polyvinyl acetate, individually (1:1 ratio), to modify the mechanical properties of the films and these films were evaluated by FTIR and scanning electron microscopy.

17 – Safety and regulatory aspects of plastics as food packaging materials

: Polymeric materials are used extensively in food packaging. In addition to the basic polymers, plastics also contain additives added in small quantities to alter the properties of the polymers in the desired way and simplify their processing. These additives along with low-molecular-weight non-polymeric components, which may remain in plastic packaging materials, possess high mobility. It is likely that some transfer of these low-molecular-weight non-polymeric components will occur from the plastic packaging material into the packaged content, thereby contaminating the product with the risk of toxic hazard to the consumer. This chapter reviews guidelines for proper use of plastics for food packaging applications and discusses the specific migration of some of the toxic additives like acetaldehyde, terephthalic acid, methyl ethyl glycol and bisphenol-A. Nanocomposites are also used in food packaging materials. There are many safety concerns about nanomaterials, as their size may allow them to penetrate into cells and eventually remain in the system. Manufacturers have to follow good manufacturing practice using only the additives listed in the positive list. Prior to categorizing such plastics as toxic, evidence regarding degree of migration of their constituents has to be ascertained. In general, migration and extraction studies need to be simultaneously conducted on actual foodstuffs under conditions that are slightly more stringent than those encountered in normal usage. Hence, for good measure, the overall migration of all the migrants put together is considered for safe use, unless they are especially toxic and their specific limits are fixed by the regulatory authorities such as: Bureau of Indian Standards, the European Commission Directives, and the Code of Federal Regulations of the US Food and Drug Administration.

Safety and regulatory aspects of plastics as food packaging materials

Abstract: Polymeric materials are used extensively in food packaging. In addition to the basic polymers, plastics also contain additives added in small quantities to alter the properties of the polymers in the desired way and simplify their processing. These additives along with low-molecular-weight non-polymeric components, which may remain in plastic packaging materials, possess high mobility. It is likely that some transfer of these low-molecular-weight non-polymeric components will occur from the plastic packaging material into the packaged content, thereby contaminating the product with the risk of toxic hazard to the consumer. This chapter reviews guidelines for proper use of plastics for food packaging applications and discusses the specific migration of some of the toxic additives like acetaldehyde, terephthalic acid, methyl ethyl glycol and bisphenol-A. Nanocomposites are also used in food packaging materials. There are many safety concerns about nanomaterials, as their size may allow them to penetrate into cells and eventually remain in the system. Manufacturers have to follow good manufacturing practice using only the additives listed in the positive list. Prior to categorizing such plastics as toxic, evidence regarding degree of migration of their constituents has to be ascertained. In general, migration and extraction studies need to be simultaneously conducted on actual foodstuffs under conditions that are slightly more stringent than those encountered in normal usage. Hence, for good measure, the overall migration of all the migrants put together is considered for safe use, unless they are especially toxic and their specific limits are fixed by the regulatory authorities such as: Bureau of Indian Standards, the European Commission Directives, and the Code of Federal Regulations of the US Food and Drug Administration.