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Vegetable Oil Processing: Extraction, Refining, and Packaging Explained
Vegetable Oil Processing: Extraction, Refining, and Packaging Explained

Introduction: The Role of Vegetable Oil in Our Diet


Vegetable oil is a vital part of the human diet, providing:


  • Fat-soluble vitamins (A, D, E, K)
  • Essential fatty acids (omega-3 and omega-6)
  • Enhanced taste, texture, and caloric value in food


Common sources include mustard, soybean, avocado, palm, sunflower, sesame, and cottonseed. The factory-level processing of these oilseeds involves:


  1. Pre-processing
  2. Extraction
  3. Refining
  4. Packaging and Storage

A food processing consultant helps design hygienic, cost-effective, and compliant vegetable oil processing lines.


Raw Material Handling and Pre-Processing


Raw Material Pre-checks

  • Sorting and grading: Remove moldy or damaged seeds
  • Cleaning: Remove stems, leaves, metal, and stones using vibrating screens, aspiration, and magnetic devices
  • Drying: Reduce moisture from ~13% to 10% using multi-column dryers


Pre-processing Methods

  • Dehulling: Removes outer layer to improve oil recovery
  • Cracking and Flaking: Increases surface area for better solvent contact
  • Conditioning: Uses steam heat to denature enzymes and enhance extraction


Extraction Methods


Mechanical Extraction

  • Done via expeller presses, screw presses, or hydraulic presses
  • Benefits: Low investment, cleaner oil
  • Limitation: Lower yield compared to solvent extraction


Chemical Extraction (Solvent)

  • Uses hexane, ethanol, methanol or other solvents
  • Steps: Conditioning → Solvent contact → Miscella separation
  • Yield: 90–98% oil recovery
  • Needs solvent recovery systems and strict safety protocols

Solvent residue must be <5 ppm due to health risks like dizziness or long-term organ damage.


Oil Refining Process


Raw oil contains free fatty acids (FFA), phospholipids, pigments, and undesirable flavors. Refining improves:

  • Stability
  • Color and clarity
  • Shelf life and taste


Key Steps in Refining:


Degumming

  • Removes gums (phospholipids, carbohydrates, trace metals)
  • Methods: Water degumming, acid degumming, enzymatic degumming


Neutralization

  • FFA neutralized with caustic soda (NaOH)
  • By-product (soap) can be separated and reused


Bleaching

  • Uses activated earth, charcoal, or silica clay under vacuum
  • Removes pigments and trace impurities


Deodorization

  • High-temperature steam distillation
  • Removes FFA, pesticides, off-flavors, and volatile contaminants


Winterization (Dewaxing)

  • Removes waxes that cause cloudiness in cold
  • Done by controlled chilling and filtration


PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering Vegetable Oil Processing Build World-Class Food Factories PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering CONTENTS 1 2 3 4 5 6 7 8 X Introduction Raw material Pre-processing methods Processing Risk status of vegetable oil processing Application Advancement in Veg. Oil Processing References About PMG Engineering Build World-Class Food Factories 2 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 1. Introduction • An essential everyday diet : component of our ✓ Adds taste and mouthfeel to food ✓ One and only source of fat-soluble vitamins and essential fatty acids. • General source of vegetable oil are fat and oil rich crops such as mustard, soyabean, avocado, palm, sunflower, etc. • Processing of oilseed crops at factory level involving- • Pre-processing of oilseed • Extraction of crude oil • Refining of crude oil. Build World-Class Food Factories Build World-Class Food Factories 3 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 1(a). Different major sources of vegetable oil # Oil producing sources Oilseed production (m. tons) in India (2022) 1. 2. 3. 4. 5. 6. 7. 8. 9. Soyabean Groundnut Mustard/ Rapeseed Sunflower seed Safflower seed Sesame seed Niger seed Castor seed Linseed 18.75 9.72 11.95 0.87 0.22 0.18 0.16 2.45 0.34 Build World-Class Food Factories 4 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 1(b). Vegetable Oil’s Fat Profile n o i t i s o p m o c d i c a y t t a F • Good source of fat-soluble vitamins Short-chain (C6–8) Ex: Butyric, capric, caproic acids, etc. and essential fatty acids. • They are all triglycerides. Medium-chain (C10–12) Ex: Decanoic, & Lauric acid Long-chain (C14–18) Ex: Myristic, Palmitic, Stearic acid Classification of fatty acid - Oils containing short-chain fatty acids are in a liquid state (at room temperature), but - oils with a large amount of medium-chain or long-chain fatty acids are in a semi-solid to solid form. • The plant oils may be saturated (completely or unsaturated having one, two, or three double bonds of the cis-configuration. hydrogenated) • If fatty acids have >2 double bonds, it is known as PUFA, including essential fatty acids. 5 Build World-Class Food Factories PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 2. Raw Material 1. Oilseed (base material) 2. Solvent (Generally hexane) 3. Acid (Phosphoric Acid/ Citric Acid) 4. Caustic Soda 5. Bleaching Clay & Activated Earth, 6. Antioxidants, And 7. Essential Oils (Natural preservative) Build World-Class Food Factories Build World-Class Food Factories 6 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 3. Pre-Processing Methods 1. Grading & sorting: To remove stones and moldy seed/nuts. 2. Cleaning/ Washing: • To remove plant stems, sticks, leaves, and foreign material before storage. • Done using a combination of rotating or vibrating coarse screens, reels, and aspiration • Magnetic devices are used to remove metal contaminants from seeds. • Destoner to remove stones present in seeds or nuts. 3. Drying: • Moisture content in oilseed received at the factory is 13 percent. Hence, drying is done up to a moisture content of 10%. • Large, vertical, open-flame grain dryers with multiple columns are generally used. Build World-Class Food Factories Build World-Class Food Factories 7 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 3. Pre-Processing Methods (Cont.) 4. Dehulling: Oilseed and nuts contain less than 1% oil content, dehulling removes the maximum quantity of hulls from the oilseed. Ex: 45% from cotton seed. 5. Size Reduction and Flaking: • Cracking and flaking increase the surface area for increased contact between the solvent and the seed. • Cracking mills having two sets of cylindrical corrugated rolls in series are used for size reduction and • Flaking mills having two large-diameter rolls in opposite directions and forced turning together by hydraulic cylinders are used for flaking. • Flake thickness: 0.25-0.37 mm Build World-Class Food Factories Build World-Class Food Factories 8 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 3. Pre-Processing Methods (Cont.) 5. Conditioning & tempering (*Optional) • To denature proteins, release oil from the cells, and inactivate enzymes (as some enzymes in the hydrolysis of compounds soluble in oil produce toxins), • Improves flaking performance and extraction efficiency. • Steps involved: Step 1: heat at 68–122oF for <5 minutes. Step 2: Contact live steam at 248oF • Done using rotating drums with an internal steam coil. Build World-Class Food Factories Build World-Class Food Factories 9 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4. Processing: Process Flow Diagram Pre-processing of Oilseed/ Nuts Extraction of Crude Oil Crude oil Degumming Separation De-gummed oil Winterization Finished Oil Oil Cake De-odorized oil De-odorization Bleached oil Filteration Bleaching Spent Earth Activated Earth Oil Foot (Crude Lecithin) Bleaching Clay @Vacuum Neutralization Separation Neutralized oil Washing & drying Build World-Class Food Factories Build World-Class Food Factories 10 Hot Water Caustic Soda PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.1 Extraction of Oil 1. Mechanical Extraction • The oldest methods of extraction • Done either by using an expeller, hydraulic screw presses, presses. Where seeds are fed into an in-between barrier that breaks seeds using applied pressure or • Good-quality oil is produced • Lower the initial investment cost • Efficient method, though very low oil yield • Require highly trained personnel to operate. Build World-Class Food Factories 11 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.1(a) Difference between expeller and cold press # Parameters Expeller Cold press 1. 2. Machine type Mechanical extraction; Mechanical presses Meticulous process; Hydraulic presses Extraction Condition Crushing & grounding without usage of chemicals or solvents Crushing and squeezing seeds at low temp. Without chemicals 3. Taste Rich; nutty undertones Lighter, more subtle 4. 5. 6. Smoke point Cooking type/ Use of oil Higher Lower Ideal for high-heat cooking like frying and sautéing. Not suitable for high heat cooking, but great for dressings, dips etc. Nutrient value of oil Keep some of the antioxidants and essential fatty acids Keeps high levels of omega-3 fatty acids and vitamin E Build World-Class Food Factories 12 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.1 Extraction of Oil (Cont.) 2. Chemical Extraction (Solvent Extraction) • Extraction of oil with the help of some chemical solvent, known as inert extraction, can be done in batch or continuous methods. • Extraction depends on the ability of the solvent to dissolve oils. • Have a 90%–98% oil recovery rate • It involves three steps: - Cleaning and conditioning, - Oil extraction, and - Separation of the miscella • It requires high energy, high investments, and solvent (hexane) may be hazardous and can cause health problems. • Solvents: n-hexane, ethanol, methanol, chloroform, petroleum ether, etc. 13 Build World-Class Food Factories PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.2 Refining • Before starting vegetable oil processing, oil is being tested to find out which processing needs to be used for the refining of crude oil. - % FFA - Phospholipids % - Moisture content, - - Colour Insoluble impurities and • Major steps involved: 1. Degumming 2. Neutralization 3. Bleaching 4. Deodorization 5. Winterization Build World-Class Food Factories 14 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 3.2(a) Degumming • • • Eliminate “gums” or “mucilage” (composed of mainly phospholipids as well as carbohydrates, proteins, and trace metals). Precipitated gums is removed after mixing using centrifugal separation. Can be done using 1. Hot water @ 60 - 70℃ 2. Acid (phosphoric or citric acid) and Hot water @60 - 70℃ 3. Enzyme (phospholipase) and Hot water @60 - 70℃ Build World-Class Food Factories 15 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.2(b) Neutralization • Vegetable oil contains high amount of free fatty acids (FFA) which can degrade the chemical quality and organoleptic quality of the oil during storage. • Why?- Due to the action of hydrolysis and oxidation, resulting in undesirable color and odor in the finished product. • What? - To eliminate these FFA up to a recommended level - caustic soda or physical refining using steam distillation is recommended. R-COOH + NaOH R-COO-Na+ + H2O # Vegetable oil Type of FFA FFA g/100g of oil (max.); FSSAI 1. 2. 3. 4. General veg. oil Oleic acid 0.7- 10 Palm oil Palmitic acid Palm kernel Coconut oil Lauric acid Lauric acid Acid Value < 6 < 10 3.0 - 10.0 (gen. 5) < 6 Build World-Class Food Factories Build World-Class Food Factories 16 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.2(b) Neutralization (cont.) • In to addition elimination of FFA, neutralization and • Additional compound such as • excess of phosphoric acid, • residual proteins, • residual gums, • carbohydrates, • oxidation products from FFA, • traces of metals, and • pigments etc., can also be removed. • As soap is insoluble in oil, it can easily be removed using mechanical separation methods. And can be further used for manufacturing of soap bars. Build World-Class Food Factories Build World-Class Food Factories 17 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.2(c) Bleaching • Complex physical and chemical process • Objective of bleaching: a. To reduce quantity of coloured pigments. b. Remove residues of phosphatide, soap, phospholipid contaminants, lipid peroxidation products, and other impurities. • Bleaching agents used for decolouration of vegetable oils are: - Special silica - adsorption bleaching clays (most popular) - activated carbon/charcoal - Combination of two or more bleaching agent Bleaching Build World-Class Food Factories Build World-Class Food Factories 18 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.2(d) De-odorization • It is a simple distillation process, involving high temperatures. • The odorization results: - Elimination of free fatty acids, - Removal of odors & off-flavor components, - Removal of contaminants (pesticides, light polycyclic aromatic hydrocarbons, and other volatile components), and - Additionally, it is also removing residues of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). Improves the stability and color of the oil, whilst preserving its nutritional value. - Build World-Class Food Factories Build World-Class Food Factories 19 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.2(e) Winterization • It is also known as dewaxing • As waxes are long-chain primary alcohols and long fatty acids, it has low solubility in oil but have high melting point due to which it crystalize during winter season. • Its presence degrades quality (cloudy appearance) of oil . • Winterization involves three steps: • Heating at 55OC • Slow cooling up to 10–15°C and holding for hours • Filteration yielding cleared oil • Examples of oils, where winterization is done are rice bran, canola, corn germ oil, sunflower, and olive pomace Build World-Class Food Factories 20 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.2(f) Packaging • The vegetable oils after processing is packed for supply in the retail market using various types of packages: 1. Rigid plastic container; made up of Plastic like HDPE/PVC/PET materials, metal such as tin can, a. Institutional pack: 15 Kg b. Family pack: 2- 5 Kg Build World-Class Food Factories 21 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.2(f) Packaging 2. 3. Semi- rigid packages: Multilayered; Capacity- 200 mL to 1L a. Lined folded carton with laminates such as met. PET,/PE,/Al foil b. Nylon based bag-in-box package Flexible packages: a. Mono-films: LDPE, HDPE, & PP pouches b. Two-layer films: Two-layer co-extruded films using LDPE/HDPE/PET/ ionomer/ PP etc. c. Three-layer film: LLDPE/LDPE/HDPE/EAA/metPET etc in composite structure and co-extruded form. d. Five layered film: LLDPE or HDPE or PP/PA/BA/PA/EAA etc., though Polyamide based co-extruded structure (most suited with FFS machine). Build World-Class Food Factories 22 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 4.2(g) Storage at warehouses • Conditions required for storage of vegetable oil: 1. Storage temp: not more than 25 OC, to maintain this temp - Inert gases such as nitrogen or ammonia is applied to the vapour space of storage container (tanks) - Pallets are used to store in controlled room. 2. Location: warehouse in air-tight container/pouch, with provision of light barrier. • The best way to store finished vegetable oil is in a tank/barrels, from where it is transported for packaging in small SKUs. Build World-Class Food Factories 23 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 5. Risk Status of Veg. Oil processing Some of food safety-based health risk Mustard oil - Erucic acid Peanut oil - Aflatoxin B1 Cotton seed - Gossypol Processed veg. oil - PAHs (benzopyrene) 1. Solvent residue in oil: (<5 ppm); Dizziness, vomiting, or even paralysis. 2. Industry-specific risk: Fire and explosion risks at processing stage due to leakage of hexane. 3. Industry-specific food safety risk; health risks of benzopyrene, aflatoxin B1, erucic acid and heavy metals (lead, arsenic, cadmium and chromium) A. Benzopyrene (a PAHs): carcinogenic risk; a processing contaminants. B. Aflatoxin B1: health risk in peanut oil. C. Erucic acid: mustard oil; cardio- vascular diseases, lungs cancer, etc. D. Gossypol: Cotton seed E. Potential presence of pathogens and contaminants (e.g., Pesticide residue). Build World-Class Food Factories Build World-Class Food Factories 24 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 5(a). Possible solution for contaminants presence 1. Inspection or raw material (Ex: oilseed) 2. Proper storage of cleaned raw material 3. Use of both methods of extraction in combination 4. Use of natural components for refining Build World-Class Food Factories Build World-Class Food Factories 25 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 7. Advancement in Veg. Oil Processing 1. Membrane technology for vegetable oil processing • Membrane processing, organic-solvent-nanofiltration has resulted in a 65% energy savings in the membrane de-solventizing of hexane oil miscella. • • It was found that it can be a better alternative to achieve degumming, deacidification, bleaching, dewaxing, catalyst recovery, etc. Hindrance for this technique in veg oil processing: - Selectivity, - Productivity, and - Durability of the membranes Vegetable oil Build World-Class Food Factories Build World-Class Food Factories 27 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering 8. References • Gharby S. Refining Vegetable Oils: Chemical and Physical Refining. Scientific World Journal. 2022 Jan 11;2022:6627013. doi: 10.1155/2022/6627013. PMID: 35069038; PMCID: PMC8767382. • Chaoting Wen, Mengyu Shen, Guoyan Liu, Xiaofang Liu, Li Liang, Youdong Li, Jixian Zhang, Xin Xu. Edible vegetable oils from oil crops: Preparation, refining, authenticity identification and application. Process Biochemistry. 2023. Volume 124, Pages 168-179, ISSN 1359-5113, https://doi.org/10.1016/j.procbio.2022.11.017. • Ying Zhou, Weiwei Zhao. Edible Plant Oil: Global Status, Health Issues, and Perspectives. Front. Plant Sci., Sec. Crop and Product Physiology. 2020 Aug 28; Volume 11 - 2020 | https://doi.org/10.3389/fpls.2020.01315 • Processes | Free Full-Text | Optimization Methods for the Extraction of Vegetable Oils: A Review (mdpi.com) • au139e.pdf (fao.org) • Ninth-Final.pmd (icpe.in) • 3 Chapter 2 (Fats, oils and fat emulsions).pdf (fssai.gov.in) • www.edibleoilextractionmachine.com • https://ars.els-cdn.com/content/image/3-s2.0-B9780123849472007078-f00707-03- 9780123849472.jpg Build World-Class Food Factories Build World-Class Food Factories 28 PMG Engineering Private Limited The End-to-End Engineering Company in Food Industry info@pmg.engineering |www.pmg.engineering Our Clients Build World-Class Food Factories Build World-Class Food Factories # We deliver End-to-End Engineering Design and Construction Management Projects in Food and Beverage Industry. Meeting Global Benchmarks In ENGINEERING DESIGN and PROJECT MANAGEMENT for FOOD and BEVERAGE Industry with SINGLE POINT ACCOUNTABILITY Process Engineering | Project Management | Mechanical | Electrical | Automation | Food Safety Key Clients We deliver End-to-End Engineering Design and Construction Management Projects in Food and Beverage Industry. Meeting Global Benchmarks In ENGINEERING DESIGN and PROJECT MANAGEMENT for FOOD and BEVERAGE Industry with SINGLE POINT ACCOUNTABILITY Process Engineering | Project Management | Mechanical | Electrical | Automation | Food Safety Key Clients We deliver End-to-End Engineering Design and Construction Management Projects in Food and Beverage Industry. Meeting Global Benchmarks In ENGINEERING DESIGN and PROJECT MANAGEMENT for FOOD and BEVERAGE Industry with SINGLE POINT ACCOUNTABILITY Process Engineering | Project Management | Mechanical | Electrical | Automation | Food Safety Key Clients
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