STARCH IN ANIMAL FEED Milica Radosavljević, Marija Milašinović, Zorica Pajić, Milomir Filipović Maize Research Institute, Zemun Polje, S. Bajića 1 Belgrade-Zemun

OBJECTIVES 1. To summarise and perceptibly present our the most important results on investigations on a starch role in animal feed and 2. To describe the utility value of grain of different ZP maize hybrids as a raw material in its production.

INTRODUCTION: STARCH AMYLOSE AMYLOPECTIN STARCH STRUCTUTE CORN AS AN IMPORTANT SOURCE OF STARCH

STARCH THE SECOND LARGEST BIOMASS IN THE WORLD HOMOPOLYSACCHARIDE-GLUCOSE POLYMER MOLECULAR FORMULA: (C 6 H 10 O 5 )n MAJOR COMPONENTS: AMYLOSE AND AMYLOPECTIN

THE CHEMICAL STRUCTURE OF AMYLOSE

THE CHEMICAL STRUCTURE OF AMYLOPECTIN

Characteristics Shape Linkage Molecular weight Films Gel formation Colour with iodine Amylose Essentially linear  -1,4 (some  -1,6) <0.5 million Strong Firm Blue Amylopectin Branched  -1,4 and  -1, million Weak Non-gelling to soft Reddish brown

Light micrograph of corn starch granules

Electron scanning micrograph of corn starch granules

Schematic representation of a starch granule (from Lineback 1984)

Schematic of the organization of a starch granule (from J. Jane 2009)

CORN IS ONE OF THE MOST IMPORTANT SOURCES OF STARCH

Animal feeding

The animal feed production is traditionally one of the greatest maize consumers. Not only in our country, but in many others, maize has suppressed almost all other cereals. The most important and unique reason for this are its chemical properties and energy values. As an essential component of the animal production, maize covers from 60 to 90% of energy necessary for functioning of the organism and for the maintenance of a body temperature. Starch is in a principal carbohydrate and at the same time is an essential chemical constituent of maize grain. Its content averagely amounts to approximately 70%.

Composition of corn grain Component Average (%) Typical range (%) StarchProteinFat Crude fiber Ash

Molecular marker assisted selection with the aim of getting a desirable genotype is now routinely applied in maize breeding programmes, which enables genetic control of a molecular starch structure, whereby its properties can be altered. The performed studies show that the starch granule structure and interactions with other components within the endosperm, as well as, processing conditions influence starch digestibility. However, in order to determine more detailed parameters of the starch structure that affect animal feed digestibility further systematic studies are necessary.

Considering directions of nutritive and technological observations, a special attention today should be paid to the development of inbreds and hybrids with specific traits and for special purposes. Studies of the structure and unique properties of starch of speciality maize hybrids are aimed at hybrids such as waxy, high amylose, high lysine and high protein hybrids, which, again, due to being a raw material for the sustainable animal feed production get their own great and deserved importance

Approximate amylose and amylopectin content of common corn starches Starch type Dent corn Waxy corn High-amylose corn Amylose(%) Amylose (%) 25< (or higher) Amylopectin (%) 75> (or lower)

What makes corn starch so versatile as an inexpensive raw material and ingredient of many feed and food products? GELATINIZATIONPASTINGRETROGRADATION EFFECTS OF pH, SHARE, AND OTHER INGRADIENTS

Starch gelatinization is the collapse (disruption) of molecular order within the starch granule manifested in irreversible changes in properties such as granular swelling, native crystalline melting, loss of birefringence, and starch solubilization. The temperature at which starch begins to undergo these changes is referred as the gelatinization temperature

Pasting is the phenomenon following in the dissolution of starch. It involves granular swelling, exudation of molecular components from the granule, and eventually, total disruption of the granules. Peak viscosity is the point at which, during heating in water, gelatinized starch reaches its maximum viscosity.

The effect of pH on starch gelatinization is an important consideration. Shear can also have a dramatic impact on starch behaviour. Because feed and food products are usually quite complex, the effect of other ingredients also has to be considered when evaluating starch functionality in terms of viscosity. Fats, sugars, proteins, and salts can all influence starch gelatinization, pasting and retrogradation.

MATERIAL AND METHODES -Nativne corn starches and grain of ZP corn hybrids. *Content of starch and other basic chemical constituents of corn grain (contents of protein, oil, crud fibre, ash) *Chemical structure and functional properties of corn starch (contents of amylose, amylipectin and resistant starch, termochemical properties and viscosity) *Maize starch and grain digestibility -enzymatic hydrolysis by  -amylase -in vitro digestibility by Tolley and Terry

RESULT AND DISCUSSION The chemical content and structure, functional properties and the digestibility of starch and maize grain, as a basic component in animal feed production, are described and discussed in this study. The content of starch and other basic chemical constituents of the grain, i.e. the chemical composition of maize grain is its most important property, not only for food and feed, but also for the remaining of its uses. As a highly yielding carbohydrate plant, maize is very competitive in regard to other cereals in the animal feed production.

Hybrid Starch (%) Protein s (%) Oil (%) Crude fibre (%) Ash (%) ZP 74b ZP ZP 300b ZP ZP ZP ZP ZP ZP 611k ZP ZP ZP ZP ZP 704wx ZP Rumenka Average Minimum Maximu m SD

Chemical structure and functional properties of maize starch Starch is one of the most important animals source of energy. The mechanisms of it degradation is very complex. The amylose to amylopectin ratio is important factor that affects the speed and the degree of starch degradation and its digestibility and consumption by animals. In recent times resistant starches have been attracting the attention of many researches world- wide due to two reasons: potential positive effects on human health that can contribute to prevention of certain diseases, as well as, due to their functional properties.

Hybrid Amylose (%) Amylopectin (%) Resistant starch (%) ZP 74b25.075,01.1 ZP ,5- ZP ,21.2 ZP ,0- ZP ZP ZP ZP 611k ZP ZP ZP ZP ZP 704wx ZP ZP ZP ZP ZP Rumenka Average Min Max Sd

HybridTo (ºC)Tp (ºC)Tc (ºC)ΔH (J g -1 ) ZP 74b ZP ZP ZP ZP 611k ZP ZP ZP 704wx ZP ZP Rumenka Average Min Max Sd The differential scanning calorimetry (DSC) method was applied to study the most important functional property, gelatinisation, and to determine thermo- chemical parameters of selected samples

The studies of gelatinisation and viscosity of maize starch are of enormous practical significance for the animal feed production, especially feed that is made by the application of a modern procedure of thermal processing of raw materials, for both the production process itself and for usability of nutrients in the animal organism. Corn starch and grain digestibility Not only the starch structure and its functional properties from the aspect of a starch role in the animal feed, but also its digestibility is also important.

CONCLUSION Results described and discussed in the present study show not only the existence of the differences related to the maize grain starch grain, its structure and functional properties, components mostly affecting maize yield as a basic component in the animal feed production, but also the existence of differences in the digestibility of different maize starches and the digestibility of maize grain that depends on the genetic background, i.e. hybrid. These results are comparable with results obtained in leading research centres all over the world.

Considering the role and the application of starch in animal feed, its chemical structure, functional properties and the digestibility represent unavoidable and very fundamental parameters. The most important chemical characteristic and the reason for maize advantage over other cereals in animal nutrition is certainly its high starch content, i.e. the high energy content. These studies are a contribution and the starting point for further studies of the fundamental and practical importance within the field of the utilisation of maize, the most important natural renewable raw material for our country in the sustainable animal feed production.