Processing of wastes from food industry

Various cellulosic wastes are available abundantly from food processing industry such as fruits and vegetable processing, breweries, starch manufacturing, dairy, pulp and paper manufacturing. These wastes are invariably having high moisture content and low nutritive value but these are palatable and can be consumed by the livestock without much problem. However, these underutilized materials frequently present problems for disposal besides causing air and water pollution. In view of their large availability and perishable nature, technologies have been developed for their utilization for feeding to the animals. For the preservation of high moisture feedstuffs following methods can be employed:

Drying: Though drying under sun is not a problem in India, this is not practicable as it requires lot of labour and space to reduce its moisture content to 8-10%. Employing the electrical drier is neither feasible nor economical under the present scenario.

Ensiling: High moisture feeds care not to be ensiled; however, mixing of such feeds with dry feeds such as straws and thereafter ensiling can be possible. But the Indian farmers are not familiar with the ensiling process and it involves labour and risk of putrefaction of ensiled material in case of any negligence.

Chemical preservation: Some chemicals such as urea and common salt may be mixed with high moisture feeds under air tight conditions. Apple pomace, a byproduct available after the juice extraction, can be used as such or after drying and enriching with nitrogen supplements. It was observed that urea enriched apple pomace can replace maize grain from the concentrate mixtures without affecting their production performance (Table 8.4). Similarly, the other high moisture wastes such as maize bran (from starch industry), spent grains (breweries) and potato wastes etc can be preserved for animal feeding. Low levels of apple pomace can be incorporated into compounded feed in place of molasses.
Fresh maize bran can be preserved by ensiling either with urea (4% DM basis or with common salt (2% DM) for one month in air tight conditions as presence of oxygen spoils this feedstuff even after treatment. Maize bran can also be utilized by the

ammoniation with 4% urea (DM basis) of its mixture with paddy straw (1: 1, fresh wt. basis) following the ensiling for one month. This approach not only makes the urea treatment of straws less laborious (no need for making the urea solution and its spraying) but also provides the avenue for the preservation and improvement in the nutritional value of maize bran or other similar high moisture wastes.