Seed Processing Technique

Seed Processing

Seed Processing

Following harvest, the seeds must be treated using a variety of procedures in order to retain physical purity and extend shelf life. This should be done before the seeds are stored. Cleaning Insects will breed in the stem parts and chaff gathered with the seeds, causing harm to the stored seeds. Cleaning should be done using either a wet or a dry manner to prevent such damage.

i. Wet cleaning – This approach can be used to clean plants that have seeds in their wet flesh. Seeds scooped from matured fruit flesh should be gathered in a receptacle and forcefully rubbed with gritty sand to remove flesh around the seeds. The seeds are then placed in a strainer and rinsed several times under running water to remove any remaining flesh or mucilage. Seeds should be dried for 10 days after cleaning before being stored. E.g. Cucumber, Tomato etc.

ii. Dry cleaning – For ripened seeds in a dry capsule / pod, this approach is utilised. Individual dry pods can be picked, or the entire plant with the pod can be plucked out and shade dried before being threshed for seed harvesting. Before being stored, seeds are softly crushed or rolled and winnowed after threshing. E.g. Paddy, Millets, Pulses, Oilseeds etc.

Winnowing: Tossing the seeds in the air to remove the chaff is an ancient way of removing the chaff from the seeds. Winnowing is done with elongated flat baskets. It aids in the removal of stem fragments, old petals, husks, and other floral components, as well as dirt mixed in with the seeds. Mechanical winnowers are also available.

Sieving : Sieving is done with sieves of various gauge sizes to separate the debris and chaff from the seeds. The heavier debris is retained in the larger sieve, while dust elements smaller than seeds are removed in the smaller sieve.

Drying of Seeds : Seed drying is the process of reducing the moisture content of a seed in order to increase the seed’s vigour and viability while also extending its storage life. It aids in the prevention of insect and disease infestations in the seeds. It’s best to dry at a lower temperature. During drying, moisture from the seed surface is evaporated first, followed by moisture from the seed’s interior layers being transported to the surface for further drying.

Various drying methods involved are:

a. Natural drying / Sun drying :It is a common method of drying in the field or threshing yard that makes use of the sun’s radiant energy. To ensure that the seeds dry uniformly, spread them out in a thin layer. Seeds with a high moisture content should be dried in the shade first, then exposed to the sun. Because it absorbs moisture from the air, sun dried seeds should not be kept open in the threshing yard at night. The major benefit of natural drying is that it is a simple and inexpensive process. However, there are a number of drawbacks, including delayed drying, a large floor area required, loss due to insect and disease assault, and significant weather hazards. Only use the sun to dry your hair in the morning and evening. Seed quality is harmed by drying in the middle of the day.

b. Artificial / Mechanical drying by using forced natural / heated air : This type of drying can be done right in the storage facility. Godowns should be equipped with ventilators that circulate outside dry air through blowers, allowing the seeds to dry. Only during the dry seasons is it feasible. In other circumstances, drying is accomplished by blowing hot outside air via a burner heater. The majority of modern dryers operate on this idea. The main benefit of this procedure is that it dries uniformly and in a short amount of time. However, the equipment and fuel requirements are too costly.

Tests to ascertain the dryness of seeds : To determine if the seeds have been adequately dried, simple conventional procedures are used. Small seeds can be crushed between the finger nails, large seeds can be bitten with the front tooth, and thin seeds can be twisted between the fingers. If they shatter with a cracking sound, the seeds have been properly dried.

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