9.4 Effects of processing on food quality and nutrition

Food processing methods can significantly impact nutrient retention and bioavailability. Some techniques enhance nutrient absorption, while others may decrease it. Understanding these effects is crucial for maintaining nutritional quality in processed foods.

Processing also influences food's sensory properties through chemical reactions and physical changes. The Maillard reaction, flavor development, texture modifications, and color alterations all play key roles in shaping the final product's taste, appearance, and overall appeal.

Nutrient Changes

Nutrient Retention and Bioavailability

Top images from around the web for Nutrient Retention and Bioavailability

• 

  Frontiers | Impact of Nutrient Availability on the Fermentation and Production of Aroma ... View original

  Is this image relevant?

• 

  11.11 Folate Functions | Nutrition View original

  Is this image relevant?

• 

  Frontiers | Bioavailability of Micronutrients From Nutrient-Dense Whole Foods: Zooming in on ... View original

  Is this image relevant?

• 

  Frontiers | Impact of Nutrient Availability on the Fermentation and Production of Aroma ... View original

  Is this image relevant?

• 

  11.11 Folate Functions | Nutrition View original

  Is this image relevant?

1 of 3

Top images from around the web for Nutrient Retention and Bioavailability

• 

  Frontiers | Impact of Nutrient Availability on the Fermentation and Production of Aroma ... View original

  Is this image relevant?

• 

  11.11 Folate Functions | Nutrition View original

  Is this image relevant?

• 

  Frontiers | Bioavailability of Micronutrients From Nutrient-Dense Whole Foods: Zooming in on ... View original

  Is this image relevant?

• 

  Frontiers | Impact of Nutrient Availability on the Fermentation and Production of Aroma ... View original

  Is this image relevant?

• 

  11.11 Folate Functions | Nutrition View original

  Is this image relevant?

1 of 3

• Processing methods can impact nutrient retention, the amount of nutrients that remain in the food after processing
• Bioavailability, the extent to which nutrients can be absorbed and utilized by the body, can be affected by processing
  • Some processing methods (cooking, fermentation) can enhance bioavailability of certain nutrients (lycopene in tomatoes, iron in spinach)
  • Other processing methods (high heat, extended storage) can decrease bioavailability of nutrients (vitamin C, folate)
• Nutrient retention and bioavailability are important considerations in food processing to ensure nutritional quality is maintained or enhanced

Enzyme Inactivation

• Enzymes are proteins that catalyze chemical reactions in foods, which can lead to undesirable changes (browning, off-flavors, texture changes)
• Processing methods often aim to inactivate enzymes to prevent these changes and extend shelf life
  • Heat treatment (blanching, pasteurization) denatures enzymes, rendering them inactive
  • Chemical treatments (acidification, sulfites) can also inhibit enzyme activity
• Enzyme inactivation is a key goal of many processing methods to maintain food quality and stability

Chemical Reactions

Maillard Reaction

• The Maillard reaction is a complex set of chemical reactions between amino acids and reducing sugars that occurs during heating of foods
• Maillard reaction products contribute to the brown color and distinct flavors of many cooked foods (bread crust, roasted coffee, grilled meats)
  • Melanoidins are brown pigments formed in the later stages of the Maillard reaction
  • Hundreds of volatile flavor compounds are generated, giving foods their characteristic aromas and tastes
• The Maillard reaction is a key factor in the development of desirable sensory properties in many processed foods

Flavor Development

• Processing methods can influence the flavor profile of foods through various chemical reactions and physical changes
• In addition to the Maillard reaction, other processes contribute to flavor development:
  • Caramelization of sugars during heating produces sweet, nutty, and bitter notes (caramel, dulce de leche)
  • Lipid oxidation can generate both desirable and undesirable flavors (roasted nuts, rancid oils)
  • Fermentation by microorganisms produces a wide range of flavors (cheese, soy sauce, kimchi)
• Flavor development is a complex interplay of chemical reactions and physical changes that occur during food processing

Physical Properties

Texture Changes

• Processing methods can significantly alter the texture of foods through various mechanisms
  • Heat treatment can soften plant tissues by breaking down cell walls and gelatinizing starch (cooked vegetables, pasta)
  • Mechanical processing (grinding, milling) reduces particle size and changes the texture of foods (flour, pureed soups)
  • Dehydration removes water, resulting in firmer, crunchier textures (dried fruits, crackers)
• Texture is a critical sensory attribute that influences consumer acceptance and enjoyment of processed foods

Color Changes

• Processing can induce color changes in foods through chemical reactions, pigment degradation, and physical alterations
  • The Maillard reaction produces brown colors in cooked foods (bread crust, seared meats)
  • Chlorophyll, the green pigment in plants, can degrade during heating, leading to olive-green colors (cooked spinach, green beans)
  • Carotenoids, red and yellow pigments, can be released or intensified by processing (tomato sauce, carrot juice)
• Color is a key visual cue that affects consumer perception and appeal of processed foods

Sensory Properties

• Sensory properties encompass the appearance, aroma, taste, texture, and overall eating experience of foods
• Processing methods can have a profound impact on sensory properties, both positively and negatively
  • Enhancing desirable sensory attributes is a primary goal of many processing techniques (roasting coffee, aging cheese)
  • However, processing can also lead to undesirable sensory changes (off-flavors, texture defects)
• Sensory evaluation is an essential tool in assessing the quality and consumer acceptability of processed foods