Agricultural Processing Flashcards
Mrii - rev mats
a series of operation in which the properties of the agricultural commodities are intentionally altered through the process
Agricultural processing, or crop processing,
the handling of crops as raw material for food, seeds, fiber, and chemical production.
Postproduction,
Agricultural processing activities
cleaning, drying, milling, canning, grinding, packing, freezing, and conditioning storage and transportation.
Agricultural and biosystems engineers must have a working background on crop processing since they play a vital role in achieving
food security, food safety, and food stability
lead to reduction of losses, thus increased yield and profit from agricultural production.
Efficient crop processing operations
plays an important and critical role in achieving food safety, food availability and security, food stability and variety, reduction of losses, and facilitating material handling operations.
Crop processing
process starts from the harvest up to when the commodities reach the consumers
Postproduction
simply the conversion of raw materials into food commodities and involves food and non-food crop handling, seed processing, and storage
Primary processing
operations include trimming, washing, curing, waxing, disease/pest control, sorting, sizing, cooling, and packing
Primary processing
involves the conversion of primary processed products into more complex food products and includes procedures such as mixing, depositing, layering, extruding, drying, fortifying, fermentation, pasteurization,
clarification, and heating
Secondary processing
disagreeable change or departure from the food’s normal state and such change can be detected with the senses of smell, taste, touch, or vision.
Food spoilage
The techniques to avoid food spoilage include destroying the microorganisms (yeasts, molds, bacteria)
deprive them of water, and suppress their growth by modifying their environment
The techniques to avoid food spoilage include destroying the microorganisms (yeasts, molds, bacteria), deprive them of water, and suppress their growth by modifying their environment. These can be accomplished by ____
thermal processing (pasteurization and sterilization), dehydration and drying, freezing, chemical preservation, and fermentation.
Postharvest losses in paddy in the Philippines according to BPRE (1996)
Harvesting:
Harvesting – 1.81 (~4.85)
Postharvest losses in paddy in the Philippines according to BPRE (1996)
Piling:
Piling – 0.54 (~1.77)
Postharvest losses in paddy in the Philippines according to BPRE (1996)
Drying:
Drying – 4.50 (0.74 to 8.70)
Postharvest losses in paddy in the Philippines according to BPRE (1996)
Threshing and cleaning:
Threshing and cleaning – 2.17 (0.04 to 5.09)
Postharvest losses in paddy in the Philippines according to BPRE (1996)
Storage:
Storage – 2.72 (0.35 to 5.20)
Postharvest losses in paddy in the Philippines according to BPRE (1996)
Milling:
Milling – 3.10 (~6.33)
Postharvest losses in paddy in the Philippines according to BPRE (1996)
Postharvest losses in paddy in the Philippines according to BPRE (1996)
6 x 8 x 16:
6 x 8 x 16 - 30 to 36 pieces
Postharvest losses in paddy in the Philippines according to BPRE (1996)
8 x 8 x 16:
8 x 8 x 16 - 25 to 30 pieces
concerned with the physical dimensions of the crop such as size, shape, volume, density, and surface area
Physical properties
mass per unit volume, including the pore spaces; dependent on the grain moisture content, foreign matter present, and variety of grain sample (paddy – 576 kg/m3, corn – 720 kg/m3)
Bulk density
measured using water displacement method and is dependent on moisture content and variety of grain sample
Particle density
ratio of voids volume to total volume and can be computed as a function of the bulk and particle densities
Porosity
slope of the sides of the grain mass when poured to rest by gravity, dependent on the grain moisture and foreign matter
Angle of repose
Angle of repose- very free flowing
30º to 38º
Angle of repose- free flowing
39º to 45º
Angle of repose- cohesive or non easy
flowing
46º and above
maximum angle at which the grain remains in equilibrium on an inclined surface, dependent on moisture and type of surface
Angle of friction
Angle of friction of rice: steel surface
27º
Angle of friction of wood along the grain
29º to 30º
this is the length, width, thickness of the physical properties of the crop
physical dimension
Angle of friction of wood across the grain
31º and above
physical dimension:
For rough rice, long grain – length > ______ , medium grain – _________ , short –length < ______.
6.5mm, 5.5 to 6.5 mm, and 5.5 mm
physical dimension: For milled rice, long grain – length is > _____ , medium grain is – ______ , short – length < _____.)
5.9 mm, 5.0 to 5.9 mm, 5.0 mm.
deal with the characteristics of light reflected from or transmitted through an object as affected by the different constituents of the object
Optical properties
concerned with the strength or resistance of a particular crop when placed under stress, e.g. corn kernels impacting a steel surface during pneumatic conveying, or rough rice passing through a rubber roll huller
Mechanical properties
describe the movement of heat into or out of a material, and how much heat it can contain
Thermal properties
concerned with the changes in sound transmitted through the material; these may be due to physiological changes in the crop, or presence of physical damage, that affect the characteristics of sound waves as they pass through the material
Acoustic properties
change in transmittance of electromagnetic radiation, radio frequency, and electrical energy that can be measured as crops undergo changes during maturation, go through stress conditions, or moisture removal
Electrical properties
the quality and the susceptibility to deterioration of the grains.
moisture content
Optimum moisture content at harvest is between
21% to 24% MCwb
Optimum moisture content for safe storage is ______ and for milling, ______.
14% MCwb and 11% MCwb
moisture content as a percentage of fresh weight of the sample
Moisture content wet basis
moisture content as a percentage of bone-dry weight of the sample.
Moisture content dry basis
method used by researchers to obtain accurate results under laboratory conditions; cumbersome and time consuming for use in the field or warehouse
Primary method
use of water, air or vacuum oven
Oven method
For water or air oven, moisture content is determined by measuring the lost in weight of a 25 to 30-g sample heated at 100 °C for 72 -
96 hours (3 - 4 days).
For vacuum oven, 25 to 30-g sample is ground and maintained at 100 °C and 25 mm pressure for
5 hrs
a 100-g grain sample is placed in a flask with 150 mL of mineral oil and heated to a temperature of 200°C. The evaporated moisture is condensed and measured in a graduated cylinder.
Distillation method (Brown-Duvel)
measures the electrical property of the grain which is dependent upon moisture content; advantage of this method is its portability and short time to make the reading.
Secondary method
The electrical resistance of the grain varies with moisture content, temperature, degree of compaction and cleanliness.
Electrical resistance method
The capacitance of the grain is affected by grain moisture content, temperature, degree of compaction and cleanliness
Electrical capacitance method
function of temperature, relative humidity, and the product; there is an equilibrium condition that exists such that there is no net exchange of moisture between the material and the air; EMC varies with temperature and RH and is usually expressed as dry basis.
Equilibrium moisture content (EMC)
For a fixed Relative Humidity and vapor pressure, as temperature is ______ , EMC ______.
increased, decreases
refers to the removal of foreign or dissimilar material and may be done by washing, screening, and hand picking
Cleaning
impurities present in the paddy which can be separated through sieves and other cleaning devices; may also include underdeveloped and shriveled kernels that are hard to remove
Dockage
traditional/common practice of cleaning grains; separate dirt and husk from the grain
Winnowing
most widely used sorting device; used in conjunction with air blast that will satisfactory clean and sort most granular
products
Screening
removes dirt and other foreign materials, may be continuous or batch type; may be performed by soaking in still or moving water or other fluids, water sprays, rotary drums, rotating brushes or shaker washer
Washing
separation of cleaned product into various quality fractions defined on the basis of size, shape, density, texture, and color
Sorting
may be done using screens, diverging belts and roller sorters of increasing opening sizes, separators, weight sorters, and color sorters using machine vision and image processing
Sorting
implies the classification of the material on the basis of commercial value and usage; done mostly by hand or through machinery;
Grading
may involve modern physical methods like color measurements, x-rays, lasers and IR rays, and microwaves; grade factors usually established based on physical, biological, and chemical characteristics
Grading
an optional pre-milling treatment given to paddy to its milling to achieve maximum recovery of head rice and to minimize breakage
Parboiling
The main objectives of _______ are (1) to increase the total and head rice yield of paddy, (2) to prevent the loss of nutrients during milling, (3) to salvage wet or damaged paddy, and (4) to mill the rice according to requirements of consumers.
parboiling
study of the physical and thermal properties of moist air and deals with methods to determine properties of moist air at known initial state or determine properties of unknown state after a defined process
Psychrometrics
mixture of dry air and low-pressure water vapor; affects the product during drying and storage operations
moist-air
temperature measured by an ordinary thermometer at thermal equilibrium with air
Dry bulb temperature (ºC)
measures the moisture content of air; measured by a thermometer whose bulb is covered with a wet wick
Wet bulb temperature (ºC)
greatest amount of moisture which can be held by dry air occurring
at saturation
Water vapor saturation partial pressure (kPa)
ratio of the water vapor actual partial pressure to saturation partial pressure, both in kPa
Relative humidity (%)
ratio of mass of water vapor to the mass of dry air
Humidity ratio, W (kg H2O/kg da)
Psychrometric properties: v (m3/kg da)
Specific volume
temperature at which water vapor condenses when moist air is cooled sufficiently.
Dew point temperature
Psychrometric properties: ρ (kg da/m3)
Density
Psychrometric properties: h (kJ/kg da)
Enthalpy
used to determine the state of the moist air when at least two psychrometric properties are known
Psychrometric chart
Psychrometric properties:
a. Dry bulb temperature
b. Wet bulb temperature
c. Water vapor saturation partial pressure
d. Relative humidity
e. Humidity ratio
f. Specific volume
g. Density
h. Dew point temperature
i. enthalpy
addition or removal of heat (change in dry bulb temperature) without change in moisture content of air (constant humidity ratio)
Sensible cooling or heating
simultaneous addition of sensible heat and water vapor resulting to increase in dry bulb temperature and humidity ratio of air
Heating and humidification
lowers both dry-bulb temperature and humidity ratio of air; both sensible and latent heat are removed from the air
Cooling and dehumidification
adiabatic process (no heat gain or heat loss) and follows a constant wet-bulb temperature line; sensible heat in the air is converted to latent heat in the added vapor
Evaporative Cooling
adiabatic mixing of two air streams with different properties and mass flow rates; final state of air mixture falls on straight line connecting the initial states of two air streams
Adiabatic mixing
Moisture content of newly harvested palay is ____to ____ which is too wet for safe storage or too wet for optimum milling.
21% to 36%
process of removing available water from the grains through evaporation by applying heated air
Drying
Categories of drying process:
- Air contact drying
- vacuum drying
- freeze drying
Drying the grains to 13% to 14% MC will render them relatively dormant and can be stored up to ______ without product deterioration.
six months
heat is transferred through the foodstuff either from heated air or from heated surfaces; water vapor is removed with the air
Air and contact drying
evaporation of water occurs more readily at lower pressures than at higher ones; heat transfer in vacuum drying is generally by conduction, sometimes by radiation
Vacuum drying
the water vapor is sublimed off frozen food
Freeze drying
drying takes place from the surface of the grain similar to evaporation from a free water surface; quite short and will proceed until free moisture disappears from the surface
Constant rate drying period
drying rate depends on the rate of moisture diffusion from the middle to the surface of the grain; drying rate is non-linear and decreases as moisture content decreases
Falling rate drying period
point where drying ceases to be constant
Critical moisture content
the moisture content to which the grain will dry after it has been exposed to the drying air for an infinite period of time
Equilibrium moisture content
used where rests or tempering periods allow the moisture to equalize throughout the grain; gives higher heated air utilization per exposure and lower actual drying time
Intermittent drying
Drying methods:
Sun drying
Mechanical drying
to burn the fuel to heat the drying air
burner
to force the heated air through the mass of grains
blower
to equalize the air pressure
plenum
to contain the grains
drying bin
burned fuel is forced through the mass of grains; efficient use of heat makes operation less expensive
Direct-fired burner
burned fuel is directed to a heat exchanger and discharged through a smokestack; the heat exchanger, in turn, heats the drying air; safer but less efficient in heat utilization and more expensive to acquire and operate Ø
Indirect-fired burner
used for high static pressure at low air volume
centrifugal type
used for large air volume at low
static pressure
Propeller type
Types of blowers:
centrifugal type and propeller type
heated air is supplied to an airtight enclosure at the bottom called plenum chamber to diffuse the air uniformly through the grain mass; 12 inches depth
Shallow-bed batch type drying bin
usually used for in-storage drying using slightly heated air to prevent over drying at the bottom and low air flow rate
Deep-bed batch type bin
consists of two parallel screen columns up to 18 inches apart; space between the columns is the bin
Continuous flow non-mixing type bin
Mixing occurs as the grains flow down the system; consists of a bin with layers of air channels shaped like inverted “V”s; each layer is offset so that the tops of the inverted “V”s split the streams of flowing grains causing the mixing action
Continuous flow mixing type bin
process of removing the husk and bran from paddy to produce milled rice
Milling
Composition of mature paddy:
hull, bran, endosperm
ratio of total weight of milled rice to the total weight of clean palay
Milling recovery
The ideal milling equipment should remove the hull (___%) and scrape off the bran (_____%) and produce the endosperm (_____%).
20%, 8-12% and 68-
72%
a milling recovery of greater than ____% produces undermilled rice and less than ___% produces over milled rice.
69%, and 69%
initial operation to remove foreign materials; precleaners make use of difference in material properties to separate grains from impurities
Pre-cleaning
rice straw, panicles, bag strings, soil particles, stones, iron parts are ____ impurities
large impurities
dust, sand, soil particles, weed seeds, insects, stones are ____ impurities
small impurities
Same size as grains:
empty grains, stones, iron parts
removal of the hull from the paddy to produce brown rice; the hulls are removed by shearing action; common hullers include under-runner disc huller, rubber roll huller, and steel husker
Hulling/husking
separation of husk (light materials) from the brown rice and un-hulled palay by blowing air and directing the husk into a cyclone for final discharge
Husk aspiration
separation of un-hulled paddy from brown rice after husk aspiration
Paddy separation
removal of the bran layer from brown rice by scraping; common whiteners include abrasion type and
friction pearler
Whitening
separation of whole rice and broken rice by using a rotating indented drum of screens
Grading
the phase of the post-harvest system during which the products are kept in such a way as to guarantee food security other than during the periods of agricultural production.
storage
process of keeping the rice in a storage structure designed to protect the product from inclement weather and pests for short or long periods of time while awaiting processing or movement to other location.
rice storage
Degradation of grains during storage depends principally on the combination of
temperature, moisture, and oxygen content.
determining factors in accelerating or delaying the complex phenomena of the biochemical transformation.
Temperature and moisture
have direct influence on the speed of development of insects and microorganisms (molds, yeasts, and bacteria), and on the premature and unseasonal germination of the grain.
Temperature and moisture
_____ content is directly related to the presence of insects, rodents, and other living organisms.
oxygen
Storage of grain in places that are ____ in oxygen causes death of insects, cessation of development of microorganisms, blockage or slowing down of biochemical phenomena of grain degradation, and favors the conservation of grain.
low
Two methods of palay storage:
bag and bulk
_____ can be stored in either in the open air or warehouse. ____ is where grain is stored in bins or silos of varying capacities.
bag, bulk
considered as a non-living organic substance, does not respire, and does not heat up during storage
milled rice
storage of milled rice is not highly recommended for _____ periods.
longer
Improper storage of ___ and ____ may cause deterioration of both their flavor and nutrition profile.
fresh fruits and vegetables
Some vegetables such as ______ can be stored for several months if certain criteria are met.
potatoes, onions, squash and rutabagas
The ideal cold storage room must be ____and ____ (7 °C to 10 °C) (45 °F to 50 °F).
dry dark and cool
Once fruits and vegetables have been cut, they should be used promptly or covered tightly and refrigerated for no more than ______ days.
two or three days
If cut fruits and vegetables have been left at room temperature for more than ____ hours, they should be discarded
2 hrs
Common Material Handling Devices:
- Belt conveyor
- Bucket elevator
- Screw conveyor
- Pneumatic conveyor
- Chain Conveyor
- Gravity Conveyor
- Cranes
- Lift and Carrying Trucks
the ff. are called
1. Belt conveyor
2. Bucket elevator
3. Screw conveyor
4. Pneumatic conveyor
5. Chain Conveyor
6. Gravity Conveyor
7. Cranes
8. Lift and Carrying Trucks
Common Material Handling Devices
____ of conveyed products should be avoided. ____ of the environment due to noise or dust by the conveying system should also be avoided.
Spillage and Pollution
