STUDY ON STORAGE OF RICE

Presented by

Swapna Sagarika Sahoo (38E/10)

Ramya Ranjan Mishra(64E/10)

ContentIntroductionObjectiveMaterials MethodologyResults and discussionConclusion

INTRODUCTION Rice is one of the most important food crops of India

in term of both area, production and consumer preference.

India is the second largest producer and consumer of rice in the world.

Rice production in India crossed the mark of 100 million MTnes in 2011-12 accounting for 22.81% of global production in that year.

Natural contamination of food grains is greatly influenced by environmental factors such as type of storage structure, temperature, RH, moisture

INTRODUCTION(Contd..) The indigenous storage structures are not suitable for

storing grains for longer periods. Metallic bins are used as a convenient means for storage of rice to prevent loss due to rodents.

But loss of rice due to moisture accumulation & infestation occurs in the metallic bin storage .

Provision of Insulation & aeration may help in preventing uneven temperature distribution and moisture accumulation in rice during storage .

Thus, we need some scientific intervention for storage of milled rice in metallic bin providing insulation and aeration to prevent enormous storage losses.

What is storage? Storage may be defined as a thermodynamic system which

includes a groups of interacting organisms and their surrounding environment and characterized by set of bio- physio-chemical properties.

Advantages of Storage Ensures against fluctuation in production. Stabilizes price. Strengthen public distribution system. Replenishes the depleted stock.

Controls measures for safe storage of rice

Aeration It is the practice of forcing small quantities of air through

stored grain to maintain quality. To accomplish this,   It is used to reduce temperature & also moisture content. It also helps prevent hot spots from developing and there by

reducing insect and microbial growth. Maintain uniformity in grain moisture content & temp. Removing odors from grain Equalizing grain moisture   Fumigant application  

Insulation & relative humidity

Insulation Insulation of product storage is done to reduce the flow

of heat from the warmer exterior ,through the walls, roofs, & floor of the storage.

Relative humidity For safe storage the RH of grain is less then 60% . So

it is very important to reduce the RH. RH is reduced by reducing the m.c. which is done by

using dehumidified refrigeration system.

 

OBJECTIVEThe present study was undertaken with the

following objectives.

To study the effect of insulation & aeration on temperature of rice stored in metallic bin

  To study the effect of insulation & aeration

on Moisture content of rice stored in metallic bin.

MATERIALS Raw rice(Two quintals ) Four metallic bins (50

kg capacity each) Perforated PVC pipe(1

inch dia.) Foam polystyrene(10mm

thickness) Digital temperature

recorder Hygrometer Hot air oven

Providing aeration Two metallic bins were

provided with aeration. 1 inch of PVC pipe was taken

& made holes on the pipe. The perforated pipe was fixed

on the centre of the bin by a 1 inch socket attached to the base of the bin & an end cap was provided on the top of the pipe.

The end cap was removed at certain interval to facilitate aeration during storage .

Providing insulation Foam polystyrene was

selected for providing insulation.

It has low thermal conductivity , low weight per cubic feet ,easy to install and availability.

To provide insulation on two metallic bins, 10 mm thickness foam was fixed on all surfaces of the bins(A-I, NA-I) using liquid fevicol.

A-NI,A-I,I-NA,NA-NI

To study the effect of aeration & insulation, the bins were marked as : A-NI, A-I ,I-NA & NA-NI

Where : A-NI: Storage bin provided with only Aeration.(No Insulation) A-I : Storage bin provided both Aeration & Insulation . I-NA : Storage bin provided only Insulation.(No aeration) NA-NI : Storage bin provided with out Aeration & Insulation.

METHODOLOGY Each metallic bins were

filled with 50 kg raw rice & kept under ambient condition for storage.

The initial moisture content of rice sample was measured by gravimetric method.

Measuring temperature and relative humidity 

Temperature was measured both at the centre(C) and side(S) of each bin after every seven days interval using digital temperature recorder.

The ambient temperature was also recorded.

Ambient relative humidity and RH inside each bin were also recorded at an interval of 7 days using hygrometer.

 Determination of Moisture Content

Rice sample were taken from the centre and side of each bin for moisture content determination by hot air oven method.

Initial weight of rice sample were taken and put into the hot air oven at 105°C.

After 24 hour it is removed from the hot air oven, cooled in desiccators and again weighed.

Insect infestation Samples of 100grams were

taken from each bin and visually inspected for insect infestation .

The weight of infested grain was taken to determine the percentage infestation

RESULTS AND DISCUSSION

Fig. 4.1 Difference in temperature of rice at the side and centre of the metallic bin

The difference in temperatures of rice at the side and centre of the bin were found to be higher under no aeration condition (Fig. 4.1).

This indicated that aeration helped in uniform temperature difference inside the bin during storage.

However, insulation was observed to be having no effect on the temperature profile.

Relative humidity

Fig 4.2.average relative humidity of different storage bins

The average RH values ranged from 66.7% to 69.4 % with ambient value of 66.8 %.

The average relative humidity values were found to be higher inside the bin under no aeration condition (Fig. 4.2).

This might be due to moisture migration due to uneven temperature distribution.

moisture content

The average moisture content decreased from 13.75 %to 10.98 % after 63 days of storage.

The decrease was due to higher ambient temperature. It was observed that there was no significant difference in

the moisture content of rice stored in the metallic bin after 63 days under the present storage conditions indicating no effect of insulation and aeration.

Insect infestation No insect infestation was found in our storage duration (63

days).

Change in moisture content of rice with storage period during storage in metallic bin

Days of

storage

A-NI A-I NA-I NA-NI Average

centre side centre Side centre side centre Side

0 13.74 13.748 13.74 13.74 13.74 13.74 13.748 13.74 13.74

21 11.72 11.53 11.81 11.70 12.17 11.88 12.20 12.14 11.89

42 11.052 10.52 11.10 10.93 12.37 11.40 11.12 11.07 11.20

63 10.76 10.55 10.87 11.14 11.30 11.23 11.09 10.92 10.98

Average

11.17 10.86 11.26 11.25 11.94 11.50 11.47 11.37

Conclusion The goal of this project was to determine the

effectiveness of aeration and insulation in managing stored rice.

Aeration can be a successful method for reducing bin temperatures in on-farm storage bins, thus protecting rice from insect infestations while still maintaining important physicochemical properties of rice such as HRY and MC.

Aeration helps in reducing relative humidity in the aerated bin.

Aeration reduces the moisture migration inside the bin hence prevents hot spots from developing .

It helps in maintaining the rice quality and reduces post harvest losses due to insects and rodents.

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