7 decrease in ECG and EGCG may have affected the antioxidant activity of the extracts because
these phenolic compounds are known to have more scavenging power than the flavan-3-ols that clearly increased: gallic acid, gallocatequin, and catechin, due to their stearic conformation and
the presence of the gallate group joined to the C ring treatments,but they were not always significant p0.05.
B. FOOD POWDER
A major reason for production in powder form is simply to prolong shelf-life of the ingredient by reducing water content; otherwise the ingredient would be degraded in its natural
biological environment. Another important reason is simple transport economics, because reducing water content reduces mass and costs of the ingredient to be transported Gustavo et al,
2010.
Food ingredient powders must possess a number of functionalities which can be broadly classified as: powder handling capability; reconstitution recombination ability and ingredient
functionality in the food product to be consumed. Poor handling during manufacture, storage and transport causes many problems which are quite common, such as no or irregular flow out of
hoppers and silos and problems associated with stickiness and caking of powders. Production and processing will determine the properties of particles and powder, such as particle size
distribution, shape, surface properties and moisture content. They will also influence ingredient functionality, for example, higher temperatures may cause denaturation of proteins and coating
may prevent the ingredient functionality from being destroyed by oxidation Aguilera et al, 2008.
It is well known that ingredient functionality in powder form may degrade over time between manufacture and final application. This depends on the sensitivity of the individual
ingredient and its exposure over time to temperature, moisture and oxygen in the air. Some ingredients are encapsulated and some powders are coated in an effort to prevent its degradation
and protect its functionality outlinedsome of the functional properties of food powders and particulates Lillford, 2002.
Powders are important ingredients in a large variety of food formulations and they are responsible for the development important product characteristics such as texture, flavour, colour
and nutritional value. Most of the powders will be used in some sort of wet formulation and therefore their functionality will depend on their interaction with water. Because the influence of
drying parameters is not the same for all materials, optimal drying conditions vary depending on the final objective: volatile retention, preservation of enzymatic activity and avoidance of protein
denaturation, fat oxidation or crystallisation. Usually, the resulting powder is made of dry particles with an average size of 30 microns and mean water activity around 0.2. The powder
outlet temperature is typically less than 100°C and the residence time is of seconds Huntington, 2004.
All these characteristics will have some effect on handling properties of powders such as: bulk and tapped densities, particle density, mixing with other powders, storage; wettability and
solubility, porosity, specific area rehydration, instantisation; flowability size, surface asperities, friability and creationexistence of dust, stability in specific atmosphere and medium
oxidation, humidification, active component release Huntington, 2004.
Study on quality evaluation instant green tea powder showed that the important quality attributes for a green tea sample was rated as taste flavor color strength. Among the quality
8 attributes, taste was the strongest attribute for both instant tea and green tea granules produced,
and strength was the weakest attribute. Sinija, 2011.
C. FREEZE CONCENTRATION
