Food Processing Notes

Food Processing

• Food processing generally refers to activities applied to primary agricultural products, transforming raw ingredients into food products.
• Food processing almost always alters the nutrient value of food. Water-soluble vitamins are most vulnerable to processing and cooking.
• Careful cooking and storage help retain nutrients.

Reasons for Food Processing

• Extending Availability: To extend availability beyond the season and location in which the food is grown.
• Expanding Uses: To expand the varieties of ways in which the food may be used.
• Improving Nutritional Value:
  • To improve the nutritional value of food, e.g., fortification of bread-making flour with folate.
• Improving Food Safety:
  • To improve the safety of food, e.g., pasteurization.
• Enhancing Sensory Qualities:
  • To enhance the organoleptic (sensory) qualities of food.
• For Convenience:
  • For convenience, e.g., ready-chopped vegetables or frozen meals.

Food Processing Examples

• Removal of unwanted outer layers.
• Chopping or slicing.
• Mincing or macerating.
• Emulsifying.
• Cooking (boiling, roasting, steaming, grilling).
• Deep frying.
• Mixing.
• Addition of gas.
• Proofing.
• Spraying.

Food Processing Methods and Health Effects

• Different processing methods result in either positive or negative health effects.
• Minimally processed foods do not change the food's essential structure or nutritional properties.
• Ultra-processed foods are the product of large-scale processing and often include manufactured ingredients.

Traditional Food Processing: Milling

• Milling and polishing are extensively used, especially for cereal grains.
• Whole Grain Definition: The term "whole grain" describes the intact grain, flour, or food that contains all three parts of the grain.
• Processed grains do not always result in refined grains.

Wholemeal vs. Refined Flour

• Removal of the bran and germ to make white flour results in:
  • Considerable loss of vitamins, minerals, dietary fiber, fatty acids, and phytochemicals.
  • Products with higher glycemic index.
• Whole grains and whole flour contain biotic substances like fructooligosaccharides.

Wheat Germ

• Wheat germ represents about $2.5$ to $3.8\%$ of total seed weight.
• Composition:
  • Lipids: $10$ to $15\%$.
  • Protein: $26$ to $30\%$.
  • Sugar: $17\%$.
  • Fiber: $1.5$ to $4.5\%$.
  • Minerals: $4\%$.
• Principal mineral constituents (in decreasing order): potassium, magnesium, calcium, zinc, manganese.

Cooking and Baking

• Nutrient content of foods after cooking may vary from the original ingredients and between different cooking methods.
• Undesirable reactions:
  • Acrylamide formation (carcinogen) when cooking starchy foods like potatoes and bread.

Fermentation and Pickling

• Food processing methods that encourage the growth of microorganisms to change taste and texture and allow for longer storage periods.

Smoking

• Process of flavoring, cooking, and preserving food by exposing it to smoke from burning or smoldering materials (e.g., wood).
• Commonly Smoked Foods: Meat and fish.
• Wood smoke compounds:
  • Phenolic compounds act as preservatives.
  • Antimicrobials (formaldehyde and organic acids).
• Smoking produces polycyclic aromatic hydrocarbons (PAHs), which are potentially carcinogenic.
• Potential concern for consumer health, especially in specific population groups.

Preservation

• Food is an unstable biological material that decays due to auto processes, chemical oxidation, and microbial growth.
• Preservation techniques:
  • Use of low temperatures.
  • Use of high temperatures.
  • Irradiation.
  • Drying.
  • Preservation with salt, sugar, and other chemicals.
  • Fermentation and pickling.