BIiopolymers-India's emerging role in global landscape

Plastics, ever since their emergence in early 1900s have literally taken over the day to day lives of human beings as they have become omnipotent in every house hold. Till the end of 18th century man was depending on natural plastic materials like Rubber and a host of other materials available in nature. One of the earliest fully synthetic plastic material viz Bakelite emerged in Belgium finding extensive applications in many spheres of human activity. Partially synthetic plastics based cellulose were made by treating cellulose with nitric acid, followed by dissolving the resulting product in alcohol that yielded a hardened version of plastic. Between 1920 and 1954 emerged a series synthetic plastics based on petroleum sources that include Polystyrene, Polyvinyl chloride, Polyethylene, Polypropylene, Polyethylene terephthalate followed by a number of modifications of these basic materials into speciality products for varied applications.

Interestingly the global production of synthetic plastics has been steadily growing in spite of the scare created by the oil crunch in 1960s and there does not appear to be any pause vis-a-vis the growth of this industry. Environmentalists and social activists are in the forefront to day to curtail the use of plastics and if possible to ban them altogether in the interest of the future of mankind. The "exhaustible" nature of fossil fuels and indestructibility of most plastics which are not biodegradable when disposed off have added new urgency in reducing manufacture and usage of synthetic plastics drastically in coming years. If a recent report regarding the pollution potential of plastics is to be believed, there are more than a billion tons of waste plastics dumped indiscriminately every where across the world, the biggest dumping ground being the water bodies including oceans.  Most plastics take more than 800 years to get degraded left to the elements in nature. 

Of the total production of synthetic plastics in the world, around 15 million tons per year, almost one third is used by the food industry for packing products that require better shelf life. From predominant use of glass bottles and metal cans till about 30 years ago, to day plastics have displaced both these materials almost totally. There are a plethora of reasons for every one to opt for plastics. They are versatile, have wide range of choice for every application, are malleable with high molecular weight, made from cheap petrochemicals, are impervious to water, Besides the food industry, a significant portion of plastics manufactured to day go for making pipes and by the building industry while those manufacturing furniture, automobiles and toys prefer plastics for many reasons. In India almost half the production is used for packaging purpose. One of the biggest constraints of using plastics by the food industry is the indiscriminate use of additives like plasticizers and fillers to make plastics superior in function and attractive to users. Of course there are strict regulations governing use of plastics for food contact applications including migration limitations which give reasonable protection to the consumer from hazards when they are used by the food processors. 

Bioplastics emerged as an alternative to synthetic plastics which may eventually be the answer to the problems posed by the latter. Bioplastics are derived from renewable biomass materials like vegetable fats and oils, starches and microbes. Their USP includes lesser emission of green house gases during production, are biodegradable either aerobically or anaerobically, leachables are not health hazards and they are recyclable. More than 50% of bioplastics produced to day are thermoplastics based on starches while cellulose plastics and poly lactic acid based plastics also are in the market. Poly-3-hydroxy butyrate (PHB), Polyhydroxy alkanoates (PHA), Poly amides (PA) are other bioploymers from which plastic materials of desired properties can be made. Of the 15 million tons (mt) of plastics produced globally, hardly 2.3 mt is accounted for by bioploymers.during 2013 while it is anticipated to increase to 3,5 mt by 2020.  

Polyamides, popularly called  Nylons are the rising star in the plastic horizon and they are widely used for engineering and high performance plastics.  They find extensive applications in various industries such as automotive, consumer goods, electrical & electronics, engineering parts, housings, building & construction, packaging, sporting goods, etc. Probably one of the biggest reasons for its phenomenal rise may be on account of Increased environmental awareness and its credentials as a material that can be made using renewable feed stocks. Its importance also is due to the structural advantage it offers for better performance than the conventionally made engineering thermoplastics. Most of them are bio-based made from Sebacic acid which is derived from Castor oil. Polyamides made from Castor oil such as those branded products like PA 11, PA 12, PA 410, PA 1010, PA 610, EcoPaxx, were launched in 2009 to meet increasing market demand for high performance durable bio-based engineering plastics. To day there are at least half a dozen manufacturers offering a wide range of castor oil based biopolymers with different functional properties. Some of them boast of high performance including high melting point of around 250C, low moisture absorption and excellent resistance to chemical substances. 

Where does India fit into this emerging scenario? India almost monopolizes production of castor oil accounting for more than 65% of global Castor output of 12.5 lakh tons per year. India also supplies 70% of world's requirement of Castor oil though there are 30 countries cultivating this hardy crop. It is rather a paradox that nothing much is done in the country to encourage cultivation of Castor and there is practically no new agronomic development that can raise productivity and quality considerably. If Castor oil fetches prices which are more than double that of other plant oils, government must encourage diverting land from some of the crops like sugarcane to Castor to increase the farmer income considerably.   

V.H.POTTY

http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com    

CHOCOLATES-CAN THE MELTING POINT BE RAISED?

Chocolate industry in a tropical country like India is constrained by the hot weather that prevails over most of the regions in the country during major part of the year. Chocolate products have refined Cocoa Mass as the main base and Cocoa fat provides the typical texture and eating pleasure characteristic of these products. Though chocolate making was known since many years, technological advances during the last 4-5 decades have enabled the industry to produce chocolates of uniform and reliable quality. The chocolate consumption is wide spread in western countries enjoying temperate climates when the product quality can be maintained during manufacture and retailing. How ever the warm climates in tropical countries near the Equator adversely affect the characteristics and handling and distribution pose stiff challenges.

Theobroma cacao, the botanical name for Cocoa is grown largely in Africa in countries like Ivory Cost and Ghana but the business of making chocolate is concentrated in the hands of a few multi national companies operating from the US and European Union. Converting raw cocoa pod into cocoa nibs and then to cocoa mass is a technology intensive process and requires a high degree of expertise and large investments. After allowing the pods to ferment for extracting the beans from the mucilaginous matrix, they are dried, roasted, shelled to yield cocoa nibs and finally ground into fine chocolate liquor which the solidifies to a mass at temperatures below 17C. Chocolate mass is then subjected high hydraulic pressure to separate the cocoa butter which is valued very much for its typical melting characteristics.

In a typical formulation of a chocolate product, cocoa mass with additions of cocoa butter and sugar is mixed, tempered and molded to give the final product with a snappy texture. It is the cocoa butter and its crystalline structure that decide the final eating quality of the product. Cocoa butter has six different crystal structure each with a different melting point range between 17C and 36C and the technology and expertise involve creating a homogeneous crystal structure which melts at 34C. This is accomplished by melting the mass to 45C and then slowly cooling to 27C to form a predominant mix of type IV and V crystals. Final procedure involves heating the product from 27C to 31C to eliminate type IV crystals leaving only type V with a melting point of 34C. The chocolates as known to day to connoisseurs cannot be made with any other fat and attempts to replace cocoa butter will definitely end up with products with biting and eating characteristics some what different from normal chocolates.

Many attempts have been made in the past to evolve chocolates with higher melting point amenable for easy handling and storage. Main strategies tried out earlier to produce high melting chocolates include enhancing network microstructure of chocolate, the addition of oil or fat binding polymers to the formula, and increasing the melting point of the fat phase. There are also many techniques that exist to generate a sugar network in chocolate, which may prevent melting. Such techniques include the incorporation of water into formulations, and processing the chocolate in such a way that some surfaces of the sugar remain uncoated by fat. The addition of oat flour, gelatin or cornstarch to chocolate as a binding polymer has also been successful in increasing heat resistance. While achieving heat resistant characteristics is technically feasible, the products so made adversely affect the flavor and texture qualities very significantly. There are many edible fats available to day for use in heat resistant chocolates but their consumer acceptability is very poor. Probably development of truly heat resistant chocolates without compromising on the quality may remain a distant dream for years to come though a little compromise on quality can throw up chocolate-like products with hard texture and changed mouth feel.

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com