SlideShare a Scribd company logo
PREPARATORY OPERATIONS IN FOOD
PROCESSING
Abid Hussain
FOOD PROCESSING
 Its not new to humans
 Early processing techniques: Sun drying, Salting
and Fermentation
 Recent include: pasteurization, canning and
concentration
 Freeze drying and irradiation are the modern
developments
FOOD PROCESSING
 “Process of transforming fresh food into
wholesome, nutritious and acceptable products
which are safe for human consumption”.
FOOD PROCESSING
PREPARATORY OPERATIONS
 Before processing, raw materials
undergo a number of operations to
get a high quality product
 Major operations used commonly are:
1. Cleaning
2. Sorting & Grading
3. Peeling
4. Size Reduction
5. Blanching
1. CLEANING
 Removal of undesirable (visible & invisible)
materials from food is called cleaning.
 It includes the removal of:
1. Damaged food
2. Insect-infested
3. Deteriorated food
4. Stones & Metal pieces
5. Removal of soil
6. Getting rid of pesticides, fungicides etc..
7. Improving the appearance
1. CLEANING
 Cleaning also includes washing while processing
fruits, vegetables, cereals, pulses and meat
products.
2. SORTING & GRADING
 Sorting ___ categorization of food based on
measurable physical property like; shape, size,
color & weight
 Grading ___ process of separating the food based
on quality
2. SORTING & GRADING
 Sorting by size and shape is carried out using
flatbed screens (flour, sugar, spices) or drum
screens (nuts, pea, pulses)
 Grading is done by screen grader, roller grader and
length grader.
3. PEELING
 Removal of protective covering from fruits &
vegetables by using knives or peelers
 Different methods are used for peeling:
1. Scalding
2. Abrasion Peeling
3. Flame Peeling
4. Lye Peeling
3. PEELING
 Scalding: dipping of fruits and vegetables in boiling
water for short period so as to ease the peeling
process. e.g; tomatoes & potatoes
 Abrasion Peeling: a large scale peeling by using
special machines (a cylindrical equipment with
rough surface) e.g; potatoes
3. PEELING
 Flame Peeling: it employs a high temperature to
burn off outer hair and peels that are then removed
by high pressure water. Used for onions.
 Lye Peeling: boiling of vegetables in 1-2% NaOH
solution to decompose pectin substances below the
epidermis and loosens the skin. Used for potatoes,
tomatoes and carrots.
4. SIZE REDUCTION
 For an easy and quick cooking of food ingredients,
their size should be reduced by using suitable
knives, slicers, choppers, dicers or grinders. Its
benefits include:
1. Easier & faster cooking
2. Improved appearance of product
3. Adds garnishing
4. Ensures uniform cooking
5. BLANCHING
 Heating of some plant food materials in hot water or
steam for a short period of time.
 Blanching serves to:
 Destroy active food enzymes
 Loosen the skin, e.g. tomatoes
 Remove adhering contaminants like soil, insects, etc.
 Remove tissue gas and reduce volume and facilitate
close filling
 Fix the green color in vegetables
5. BLANCHING
 Blanching time at home is 2-5 minutes in boiling
water, while it is same for industry in live steam.
 Effectiveness of blanching is determined by
evaluating activity of peroxidase or catalase
enzymes.
5. BLANCHING
 Certain chemicals are also added to blanching
water to improve the process.
 Calcium chloride is added to firm fruits.
 Ascorbic acid, Sodium chloride, Magnesium oxide,
Sodium metabisulphite, Sodium bicarbonate and
some others are used to preserve color and
retention of vitamin C.
6. SULPHURING / SULPHITING
 With some dried products, the use of chemical
preservatives will improve the color and increase the
shelf-life.
 The most commonly used preservative is sulphur
dioxide.
 There are two methods: sulphuring and sulphiting.
 Sulphuring is more commonly used for fruits, and
sulphiting for vegetables.
 Sulphiting involves the use of sulphite salts, such as
sodium sulphite or sodium metabisulphite. They may be
either added to the blanching water or more commonly
used by soaking the food in a solution of the salts.
6. SULPHURING / SULPHITING
 Sulphuring is achieved by burning sulphur in a sulphur
cabinet. This can be made from locally available
materials.
 The amount of sulphur used and the time of exposure
depend on
 the commodity
 its moisture content
 levels permitted in the final product
 The food is placed inside the cabinet and sufficient
sulphur is placed in a container near the trays. For most
vegetables 10-12 g of sulphur (22½ level teaspoons) per
kg of food is adequate. The sulphur is ignited and
allowed to burn in the enclosed cabinet for 1-3 hours.
Preparatory Operations in Food Processing.pptx

More Related Content

What's hot

Microbial spoilage of milk and milk product
Microbial spoilage of milk and milk productMicrobial spoilage of milk and milk product
Microbial spoilage of milk and milk product
Tribhuwan university
 
Bacteria in food science
Bacteria in food scienceBacteria in food science
Bacteria in food science
Nugurusaichandan
 
Preservation by chemicals
Preservation by chemicalsPreservation by chemicals
Preservation by chemicals
Nugurusaichandan
 
Yogurt
YogurtYogurt
Yogurt
scuffruff
 
Microorganisms and their role in food technology
Microorganisms and their role in food technologyMicroorganisms and their role in food technology
Microorganisms and their role in food technology
JOMIN JOSE
 
Fermented food products
Fermented food products Fermented food products
Fermented food products
Seshan Siva
 
Microbiology:General Principles of Food Preservation
Microbiology:General Principles of Food PreservationMicrobiology:General Principles of Food Preservation
Microbiology:General Principles of Food Preservation
St Mary's College,Thrissur,Kerala
 
Contamination of foods
Contamination of foodsContamination of foods
Contamination of foods
Dr. Poshadri Achinna
 
Microbial spoilage of fruits & vegetables
Microbial spoilage of fruits & vegetablesMicrobial spoilage of fruits & vegetables
Microbial spoilage of fruits & vegetables
9404577899
 
FOOD SPOILAGE
FOOD SPOILAGEFOOD SPOILAGE
FOOD SPOILAGE
HARISH J
 
History of food microbiology
History of food microbiologyHistory of food microbiology
History of food microbiology
Dr. Sujeet Kumar Mrityunjay
 
Food spoilage ppt document
Food spoilage ppt documentFood spoilage ppt document
Food spoilage ppt document
dipikasahu1
 
Biopreservatives
BiopreservativesBiopreservatives
Biopreservatives
Punjabi university
 
Classification of food
Classification of foodClassification of food
Classification of food
Muhammad Hannan
 
Microorganisms in food
Microorganisms in foodMicroorganisms in food
Microorganisms in food
Balwant Insa
 
Role of Microorganisms in Preparation of Certain Foods, in Spoilage of Food, ...
Role of Microorganisms in Preparation of Certain Foods, in Spoilage of Food, ...Role of Microorganisms in Preparation of Certain Foods, in Spoilage of Food, ...
Role of Microorganisms in Preparation of Certain Foods, in Spoilage of Food, ...
Umay Habiba
 
Biopreservatives i
Biopreservatives iBiopreservatives i
Biopreservatives i
Munna Joy
 
Food Microbiology - Chapter 3
Food Microbiology - Chapter 3Food Microbiology - Chapter 3
Food Microbiology - Chapter 3
Alia Najiha
 
Contamination, Spoilage and preservation of Fruits and Vegetables
Contamination, Spoilage and preservation of Fruits and VegetablesContamination, Spoilage and preservation of Fruits and Vegetables
Contamination, Spoilage and preservation of Fruits and Vegetables
SuganthiA4
 
Preservation methods
  Preservation methods  Preservation methods

What's hot (20)

Microbial spoilage of milk and milk product
Microbial spoilage of milk and milk productMicrobial spoilage of milk and milk product
Microbial spoilage of milk and milk product
 
Bacteria in food science
Bacteria in food scienceBacteria in food science
Bacteria in food science
 
Preservation by chemicals
Preservation by chemicalsPreservation by chemicals
Preservation by chemicals
 
Yogurt
YogurtYogurt
Yogurt
 
Microorganisms and their role in food technology
Microorganisms and their role in food technologyMicroorganisms and their role in food technology
Microorganisms and their role in food technology
 
Fermented food products
Fermented food products Fermented food products
Fermented food products
 
Microbiology:General Principles of Food Preservation
Microbiology:General Principles of Food PreservationMicrobiology:General Principles of Food Preservation
Microbiology:General Principles of Food Preservation
 
Contamination of foods
Contamination of foodsContamination of foods
Contamination of foods
 
Microbial spoilage of fruits & vegetables
Microbial spoilage of fruits & vegetablesMicrobial spoilage of fruits & vegetables
Microbial spoilage of fruits & vegetables
 
FOOD SPOILAGE
FOOD SPOILAGEFOOD SPOILAGE
FOOD SPOILAGE
 
History of food microbiology
History of food microbiologyHistory of food microbiology
History of food microbiology
 
Food spoilage ppt document
Food spoilage ppt documentFood spoilage ppt document
Food spoilage ppt document
 
Biopreservatives
BiopreservativesBiopreservatives
Biopreservatives
 
Classification of food
Classification of foodClassification of food
Classification of food
 
Microorganisms in food
Microorganisms in foodMicroorganisms in food
Microorganisms in food
 
Role of Microorganisms in Preparation of Certain Foods, in Spoilage of Food, ...
Role of Microorganisms in Preparation of Certain Foods, in Spoilage of Food, ...Role of Microorganisms in Preparation of Certain Foods, in Spoilage of Food, ...
Role of Microorganisms in Preparation of Certain Foods, in Spoilage of Food, ...
 
Biopreservatives i
Biopreservatives iBiopreservatives i
Biopreservatives i
 
Food Microbiology - Chapter 3
Food Microbiology - Chapter 3Food Microbiology - Chapter 3
Food Microbiology - Chapter 3
 
Contamination, Spoilage and preservation of Fruits and Vegetables
Contamination, Spoilage and preservation of Fruits and VegetablesContamination, Spoilage and preservation of Fruits and Vegetables
Contamination, Spoilage and preservation of Fruits and Vegetables
 
Preservation methods
  Preservation methods  Preservation methods
Preservation methods
 

Similar to Preparatory Operations in Food Processing.pptx

Food preservation and storage
Food preservation and storageFood preservation and storage
Food preservation and storage
Namita Batra
 
FOOD PRESERVATION,SAFETYAND SHELF LIFE EXTENSION.pptx
FOOD PRESERVATION,SAFETYAND SHELF LIFE EXTENSION.pptxFOOD PRESERVATION,SAFETYAND SHELF LIFE EXTENSION.pptx
FOOD PRESERVATION,SAFETYAND SHELF LIFE EXTENSION.pptx
NavajeevanBuraga1
 
Food Preservation
Food PreservationFood Preservation
Food Preservation
guest1f0df8
 
Convenience foods
Convenience foodsConvenience foods
Convenience foods
Praveen Rathod
 
Food preservation and additives ppt
Food preservation and additives pptFood preservation and additives ppt
Food preservation and additives ppt
Nidhi Choudhary
 
Food-Processing-7-Villanueva-PPT- about food7.ppt
Food-Processing-7-Villanueva-PPT- about food7.pptFood-Processing-7-Villanueva-PPT- about food7.ppt
Food-Processing-7-Villanueva-PPT- about food7.ppt
FSBTLEDNathanVince
 
Pres3. Processing by Application of Heat
Pres3. Processing by Application of HeatPres3. Processing by Application of Heat
Pres3. Processing by Application of Heat
Yimer Mihretie
 
Contamination, preservation, and spoilage of fruits and vegetables
Contamination, preservation, and spoilage of fruits and vegetablesContamination, preservation, and spoilage of fruits and vegetables
Contamination, preservation, and spoilage of fruits and vegetables
Dr. Poshadri Achinna
 
Chapter 1 Food Processing.pptx
Chapter 1 Food Processing.pptxChapter 1 Food Processing.pptx
Chapter 1 Food Processing.pptx
SandreWaldenSCSC
 
food_processing-1.ppt
food_processing-1.pptfood_processing-1.ppt
food_processing-1.ppt
GokulC37
 
Preservatives in fruits and Vegetables (Chemical and physical, Canning in det...
Preservatives in fruits and Vegetables (Chemical and physical, Canning in det...Preservatives in fruits and Vegetables (Chemical and physical, Canning in det...
Preservatives in fruits and Vegetables (Chemical and physical, Canning in det...
SaiLakshmi891734
 
food_processing-1.ppt
food_processing-1.pptfood_processing-1.ppt
food_processing-1.ppt
AbdirahmanJibrilWars
 
Dehydration
DehydrationDehydration
Dehydration
Mayur Kadam
 
Food preservation methods
Food preservation methodsFood preservation methods
Food preservation methods
Rinaldo John
 
Food processing, types , advantages , explanation
Food processing, types , advantages , explanationFood processing, types , advantages , explanation
Food processing, types , advantages , explanation
wasihaider16
 
food_processing-1.ppt
food_processing-1.pptfood_processing-1.ppt
food_processing-1.ppt
MrinmoyRoy34
 
Food spoilage1
Food spoilage1Food spoilage1
Food spoilage1
Shafiya Zareen
 
Food preservation technologies.pptx
Food preservation technologies.pptxFood preservation technologies.pptx
Food preservation technologies.pptx
DeviduttaNayak6
 
methodsofcooking-FISH.pptx
methodsofcooking-FISH.pptxmethodsofcooking-FISH.pptx
methodsofcooking-FISH.pptx
Ma. Ann Criselda Arceta
 
methodsofcooking-FISH.pptx
methodsofcooking-FISH.pptxmethodsofcooking-FISH.pptx
methodsofcooking-FISH.pptx
Ma. Ann Criselda Arceta
 

Similar to Preparatory Operations in Food Processing.pptx (20)

Food preservation and storage
Food preservation and storageFood preservation and storage
Food preservation and storage
 
FOOD PRESERVATION,SAFETYAND SHELF LIFE EXTENSION.pptx
FOOD PRESERVATION,SAFETYAND SHELF LIFE EXTENSION.pptxFOOD PRESERVATION,SAFETYAND SHELF LIFE EXTENSION.pptx
FOOD PRESERVATION,SAFETYAND SHELF LIFE EXTENSION.pptx
 
Food Preservation
Food PreservationFood Preservation
Food Preservation
 
Convenience foods
Convenience foodsConvenience foods
Convenience foods
 
Food preservation and additives ppt
Food preservation and additives pptFood preservation and additives ppt
Food preservation and additives ppt
 
Food-Processing-7-Villanueva-PPT- about food7.ppt
Food-Processing-7-Villanueva-PPT- about food7.pptFood-Processing-7-Villanueva-PPT- about food7.ppt
Food-Processing-7-Villanueva-PPT- about food7.ppt
 
Pres3. Processing by Application of Heat
Pres3. Processing by Application of HeatPres3. Processing by Application of Heat
Pres3. Processing by Application of Heat
 
Contamination, preservation, and spoilage of fruits and vegetables
Contamination, preservation, and spoilage of fruits and vegetablesContamination, preservation, and spoilage of fruits and vegetables
Contamination, preservation, and spoilage of fruits and vegetables
 
Chapter 1 Food Processing.pptx
Chapter 1 Food Processing.pptxChapter 1 Food Processing.pptx
Chapter 1 Food Processing.pptx
 
food_processing-1.ppt
food_processing-1.pptfood_processing-1.ppt
food_processing-1.ppt
 
Preservatives in fruits and Vegetables (Chemical and physical, Canning in det...
Preservatives in fruits and Vegetables (Chemical and physical, Canning in det...Preservatives in fruits and Vegetables (Chemical and physical, Canning in det...
Preservatives in fruits and Vegetables (Chemical and physical, Canning in det...
 
food_processing-1.ppt
food_processing-1.pptfood_processing-1.ppt
food_processing-1.ppt
 
Dehydration
DehydrationDehydration
Dehydration
 
Food preservation methods
Food preservation methodsFood preservation methods
Food preservation methods
 
Food processing, types , advantages , explanation
Food processing, types , advantages , explanationFood processing, types , advantages , explanation
Food processing, types , advantages , explanation
 
food_processing-1.ppt
food_processing-1.pptfood_processing-1.ppt
food_processing-1.ppt
 
Food spoilage1
Food spoilage1Food spoilage1
Food spoilage1
 
Food preservation technologies.pptx
Food preservation technologies.pptxFood preservation technologies.pptx
Food preservation technologies.pptx
 
methodsofcooking-FISH.pptx
methodsofcooking-FISH.pptxmethodsofcooking-FISH.pptx
methodsofcooking-FISH.pptx
 
methodsofcooking-FISH.pptx
methodsofcooking-FISH.pptxmethodsofcooking-FISH.pptx
methodsofcooking-FISH.pptx
 

Recently uploaded

Agriculture Market : Global Trends and Forecast Analysis (2023-2032)
Agriculture Market : Global Trends and Forecast Analysis (2023-2032)Agriculture Market : Global Trends and Forecast Analysis (2023-2032)
Agriculture Market : Global Trends and Forecast Analysis (2023-2032)
PriyanshiSingh187645
 
一比一原版美国宾夕法尼亚州立大学毕业证(penstate学位证)如何办理
一比一原版美国宾夕法尼亚州立大学毕业证(penstate学位证)如何办理一比一原版美国宾夕法尼亚州立大学毕业证(penstate学位证)如何办理
一比一原版美国宾夕法尼亚州立大学毕业证(penstate学位证)如何办理
p74xokfq
 
Top 12 Best Restaurants in Panchkula city
Top 12 Best Restaurants in Panchkula cityTop 12 Best Restaurants in Panchkula city
Top 12 Best Restaurants in Panchkula city
Tricity help post
 
Discover the Magic 7 Fruits for Weight Loss You Need to Know About!.pdf
Discover the Magic 7 Fruits for Weight Loss You Need to Know About!.pdfDiscover the Magic 7 Fruits for Weight Loss You Need to Know About!.pdf
Discover the Magic 7 Fruits for Weight Loss You Need to Know About!.pdf
RapidLeaks
 
Exploring_Karnali_Region_of_Nepal_(Food, Culture and People).pptx
Exploring_Karnali_Region_of_Nepal_(Food, Culture and People).pptxExploring_Karnali_Region_of_Nepal_(Food, Culture and People).pptx
Exploring_Karnali_Region_of_Nepal_(Food, Culture and People).pptx
Lincoln University
 
Science Text Book characteristics and library
Science Text Book characteristics and libraryScience Text Book characteristics and library
Science Text Book characteristics and library
Jerslin Muller
 
一比一原版(Bristol毕业证)布里斯托大学毕业证如何办理
一比一原版(Bristol毕业证)布里斯托大学毕业证如何办理一比一原版(Bristol毕业证)布里斯托大学毕业证如何办理
一比一原版(Bristol毕业证)布里斯托大学毕业证如何办理
uhyqho
 
Coffee Presentation Coffee in the CordillerasPDF.pdf
Coffee Presentation Coffee in the CordillerasPDF.pdfCoffee Presentation Coffee in the CordillerasPDF.pdf
Coffee Presentation Coffee in the CordillerasPDF.pdf
ronnelapilado23
 
一比一原版美国俄克拉荷马城市大学毕业证(ocu学位证)如何办理
一比一原版美国俄克拉荷马城市大学毕业证(ocu学位证)如何办理一比一原版美国俄克拉荷马城市大学毕业证(ocu学位证)如何办理
一比一原版美国俄克拉荷马城市大学毕业证(ocu学位证)如何办理
p74xokfq
 
Food smoking- processing & preservation.pptx
Food smoking- processing & preservation.pptxFood smoking- processing & preservation.pptx
Food smoking- processing & preservation.pptx
KalyaniThoteLondhe
 
一比一原版美国俄克拉荷马大学毕业证(ou学位证)如何办理
一比一原版美国俄克拉荷马大学毕业证(ou学位证)如何办理一比一原版美国俄克拉荷马大学毕业证(ou学位证)如何办理
一比一原版美国俄克拉荷马大学毕业证(ou学位证)如何办理
p74xokfq
 
按照学校原版(KCL文凭证书)伦敦国王学院毕业证快速办理
按照学校原版(KCL文凭证书)伦敦国王学院毕业证快速办理按照学校原版(KCL文凭证书)伦敦国王学院毕业证快速办理
按照学校原版(KCL文凭证书)伦敦国王学院毕业证快速办理
vdabso
 

Recently uploaded (12)

Agriculture Market : Global Trends and Forecast Analysis (2023-2032)
Agriculture Market : Global Trends and Forecast Analysis (2023-2032)Agriculture Market : Global Trends and Forecast Analysis (2023-2032)
Agriculture Market : Global Trends and Forecast Analysis (2023-2032)
 
一比一原版美国宾夕法尼亚州立大学毕业证(penstate学位证)如何办理
一比一原版美国宾夕法尼亚州立大学毕业证(penstate学位证)如何办理一比一原版美国宾夕法尼亚州立大学毕业证(penstate学位证)如何办理
一比一原版美国宾夕法尼亚州立大学毕业证(penstate学位证)如何办理
 
Top 12 Best Restaurants in Panchkula city
Top 12 Best Restaurants in Panchkula cityTop 12 Best Restaurants in Panchkula city
Top 12 Best Restaurants in Panchkula city
 
Discover the Magic 7 Fruits for Weight Loss You Need to Know About!.pdf
Discover the Magic 7 Fruits for Weight Loss You Need to Know About!.pdfDiscover the Magic 7 Fruits for Weight Loss You Need to Know About!.pdf
Discover the Magic 7 Fruits for Weight Loss You Need to Know About!.pdf
 
Exploring_Karnali_Region_of_Nepal_(Food, Culture and People).pptx
Exploring_Karnali_Region_of_Nepal_(Food, Culture and People).pptxExploring_Karnali_Region_of_Nepal_(Food, Culture and People).pptx
Exploring_Karnali_Region_of_Nepal_(Food, Culture and People).pptx
 
Science Text Book characteristics and library
Science Text Book characteristics and libraryScience Text Book characteristics and library
Science Text Book characteristics and library
 
一比一原版(Bristol毕业证)布里斯托大学毕业证如何办理
一比一原版(Bristol毕业证)布里斯托大学毕业证如何办理一比一原版(Bristol毕业证)布里斯托大学毕业证如何办理
一比一原版(Bristol毕业证)布里斯托大学毕业证如何办理
 
Coffee Presentation Coffee in the CordillerasPDF.pdf
Coffee Presentation Coffee in the CordillerasPDF.pdfCoffee Presentation Coffee in the CordillerasPDF.pdf
Coffee Presentation Coffee in the CordillerasPDF.pdf
 
一比一原版美国俄克拉荷马城市大学毕业证(ocu学位证)如何办理
一比一原版美国俄克拉荷马城市大学毕业证(ocu学位证)如何办理一比一原版美国俄克拉荷马城市大学毕业证(ocu学位证)如何办理
一比一原版美国俄克拉荷马城市大学毕业证(ocu学位证)如何办理
 
Food smoking- processing & preservation.pptx
Food smoking- processing & preservation.pptxFood smoking- processing & preservation.pptx
Food smoking- processing & preservation.pptx
 
一比一原版美国俄克拉荷马大学毕业证(ou学位证)如何办理
一比一原版美国俄克拉荷马大学毕业证(ou学位证)如何办理一比一原版美国俄克拉荷马大学毕业证(ou学位证)如何办理
一比一原版美国俄克拉荷马大学毕业证(ou学位证)如何办理
 
按照学校原版(KCL文凭证书)伦敦国王学院毕业证快速办理
按照学校原版(KCL文凭证书)伦敦国王学院毕业证快速办理按照学校原版(KCL文凭证书)伦敦国王学院毕业证快速办理
按照学校原版(KCL文凭证书)伦敦国王学院毕业证快速办理
 

Preparatory Operations in Food Processing.pptx

  • 1. PREPARATORY OPERATIONS IN FOOD PROCESSING Abid Hussain
  • 2. FOOD PROCESSING  Its not new to humans  Early processing techniques: Sun drying, Salting and Fermentation  Recent include: pasteurization, canning and concentration  Freeze drying and irradiation are the modern developments
  • 3. FOOD PROCESSING  “Process of transforming fresh food into wholesome, nutritious and acceptable products which are safe for human consumption”.
  • 5. PREPARATORY OPERATIONS  Before processing, raw materials undergo a number of operations to get a high quality product  Major operations used commonly are: 1. Cleaning 2. Sorting & Grading 3. Peeling 4. Size Reduction 5. Blanching
  • 6. 1. CLEANING  Removal of undesirable (visible & invisible) materials from food is called cleaning.  It includes the removal of: 1. Damaged food 2. Insect-infested 3. Deteriorated food 4. Stones & Metal pieces 5. Removal of soil 6. Getting rid of pesticides, fungicides etc.. 7. Improving the appearance
  • 7. 1. CLEANING  Cleaning also includes washing while processing fruits, vegetables, cereals, pulses and meat products.
  • 8. 2. SORTING & GRADING  Sorting ___ categorization of food based on measurable physical property like; shape, size, color & weight  Grading ___ process of separating the food based on quality
  • 9. 2. SORTING & GRADING  Sorting by size and shape is carried out using flatbed screens (flour, sugar, spices) or drum screens (nuts, pea, pulses)  Grading is done by screen grader, roller grader and length grader.
  • 10. 3. PEELING  Removal of protective covering from fruits & vegetables by using knives or peelers  Different methods are used for peeling: 1. Scalding 2. Abrasion Peeling 3. Flame Peeling 4. Lye Peeling
  • 11. 3. PEELING  Scalding: dipping of fruits and vegetables in boiling water for short period so as to ease the peeling process. e.g; tomatoes & potatoes  Abrasion Peeling: a large scale peeling by using special machines (a cylindrical equipment with rough surface) e.g; potatoes
  • 12. 3. PEELING  Flame Peeling: it employs a high temperature to burn off outer hair and peels that are then removed by high pressure water. Used for onions.  Lye Peeling: boiling of vegetables in 1-2% NaOH solution to decompose pectin substances below the epidermis and loosens the skin. Used for potatoes, tomatoes and carrots.
  • 13. 4. SIZE REDUCTION  For an easy and quick cooking of food ingredients, their size should be reduced by using suitable knives, slicers, choppers, dicers or grinders. Its benefits include: 1. Easier & faster cooking 2. Improved appearance of product 3. Adds garnishing 4. Ensures uniform cooking
  • 14. 5. BLANCHING  Heating of some plant food materials in hot water or steam for a short period of time.  Blanching serves to:  Destroy active food enzymes  Loosen the skin, e.g. tomatoes  Remove adhering contaminants like soil, insects, etc.  Remove tissue gas and reduce volume and facilitate close filling  Fix the green color in vegetables
  • 15. 5. BLANCHING  Blanching time at home is 2-5 minutes in boiling water, while it is same for industry in live steam.  Effectiveness of blanching is determined by evaluating activity of peroxidase or catalase enzymes.
  • 16. 5. BLANCHING  Certain chemicals are also added to blanching water to improve the process.  Calcium chloride is added to firm fruits.  Ascorbic acid, Sodium chloride, Magnesium oxide, Sodium metabisulphite, Sodium bicarbonate and some others are used to preserve color and retention of vitamin C.
  • 17. 6. SULPHURING / SULPHITING  With some dried products, the use of chemical preservatives will improve the color and increase the shelf-life.  The most commonly used preservative is sulphur dioxide.  There are two methods: sulphuring and sulphiting.  Sulphuring is more commonly used for fruits, and sulphiting for vegetables.  Sulphiting involves the use of sulphite salts, such as sodium sulphite or sodium metabisulphite. They may be either added to the blanching water or more commonly used by soaking the food in a solution of the salts.
  • 18. 6. SULPHURING / SULPHITING  Sulphuring is achieved by burning sulphur in a sulphur cabinet. This can be made from locally available materials.  The amount of sulphur used and the time of exposure depend on  the commodity  its moisture content  levels permitted in the final product  The food is placed inside the cabinet and sufficient sulphur is placed in a container near the trays. For most vegetables 10-12 g of sulphur (22½ level teaspoons) per kg of food is adequate. The sulphur is ignited and allowed to burn in the enclosed cabinet for 1-3 hours.