Lesson 11

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Oct 30, 2023

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Effects of Food Processing Operations on Nutrient Retention in Foods LESSON 11 1

Effects of Food Processing Operations on Nutrient Retention in Foods 2

Lesson Objective ▪ Outline the main factors that affect the extent of nutrient loss as a result of processing ▪ Distinguish between the benefits and drawbacks of food processing ▪ Discuss the strategies that can be used to minimize the potential loss of nutritional value in processed foods 3

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Recommended Reading 4 – “ Effects of Food Processing on Nutritive Values ” USDA Table of Nutrient Retention Factors

5 Benefits: ▪ Safety (destroy pathogens) ▪ Enhanced shelf life (destroy spoilage organisms, inactivate enzymes, reduce rate of chemical reactions) ▪ Improved digestibility of some components ▪ Destruction of some anti-nutritional compounds (e.g. proteinase inhibitors, avidin, enzymes such as thiaminase) ▪ Increased variety or enhanced palatability of some foods Risk-benefit analysis of food processing

6 Benefits: ▪ safety (destroy pathogens) ▪ Enhanced shelf life (destroy spoilage organisms, inactivate enzymes, reduce rate of chemical reactions) ▪ Improved digestibility of some components ▪ Destroy some anti-nutritional compounds (e.g proteinase inhibitors, avidin , enzymes such as thiaminase ) ▪ Increased variety or enhanced palatability of some foods Risk-benefit analysis of food processing Avidin (protein), combines with biotin (B-vitamin) = avidin-biotin complex Not absorbed from the intestine " non-digestible " Enzyme found in a few plants, raw flesh & viscera of some fish & shellfish. When ingested this enzyme splits thiamin (Vitamin B1) = Inactive.

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7 Risks: ▪ Possible production of undesirable (sensory) or potentially toxic (at high doses) new compounds ▪ Decreased nutrient value ▪ Risk of microbial resistance if inadequate processing treatments are used. Risk-benefit analysis of food processing

8 Depends on: 1. Type of nutrient 2. Properties of the food 3. Processing method and conditions What is the extent of nutrient loss as a result of processing?

9 Depends on: 1. Type of nutrient ◼ some nutrients are more stable than others ◼ E.g. vitamins are more unstable than minerals… What is the extent of nutrient loss as a result of processing?

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What are the effects of processing on nutrients other than vitamins ? Minerals Stable- physical loss (e.g. leaching, milling) Proteins & Carbohydrates Digestibility/Bioavailability (+) losses usually only after severe treatments, extreme pH Fats Little change after moderate processes Prone to hydrolytic and oxidative reactions: ◦ prolonged storage in presence of O 2 ◦ excessively high Temp or pH ◦ Enzymatic action (e.g. lipases) ◦ irradiation in presence of O 2 10

11 Depends on: 2. Properties of the food ◼ Stability may vary with pH ◼ e.g. Vit. A unstable at pH <7.0; Vit. C at pH ≥7.0 (Table 2) ◼ Vit. E remains stable at broad range of pH ◼ e.g. high acid food - less severe thermal process than low acid food → less loss of nutrients ◼ Food properties affect the process ◼ e.g. heat transfer is slower in solid ( conduction ) than liquid ( convection ) products What is the extent of nutrient loss as a result of processing?

12 Depends on: 3. Processing methods and conditions ▪ Thermal processing : (Tables 3-5) ▪ severity of the process – blanching vs canning ▪ method used – e.g. microwave, canning, HTST or UHT vs LTH ▪ cooking in water (leaching) vs steam, microwave, stir-fry, bake What is the extent of nutrient loss as a result of processing?

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13 USDA Table of Nutrient Retention Factors

14 Depends on: 3. Processing methods and conditions ▪ Thermal processing : (Tables 3-5) ▪ severity of the process – blanching vs canning ▪ method used – e.g. microwave, canning, HTST or UHT vs LTH ▪ cooking in water (leaching) vs steam, microwave, stir-fry, bake ▪ Irradiation ▪ Thiamin (Vitamin B1) is the most vulnerable ▪ Freezing ▪ can help preserve nutrients compared to other processing methods. ▪ What is the extent of nutrient loss as a result of processing?

Depends on: 3. Storage ❑ Environmental conditions : oxygen, light, heat, moisture… ❑ Type of packaging 15 What is the extent of nutrient loss as a result of processing?

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16 May be accomplished by: ◼ Restoration (replacement) ◼ Fortification (addition- not previously present ) ◼ Enrichment aka Mandatory Fortification (achieve specific levels requested by regulation) Regulatory decisions: which foods may be approved for nutrient addition, and whether optional or mandatory Nutrient addition

17 Questions and Recommended Activities Reading: “ Effects of processing on Nutrient values… ” - Overview of changes in nutrients as a function of processing: -Which processing method results in a nutritive quality closest to that of fresh, raw foods? -What are the “ pluses and minuses ” of food processing? -What are the main factors affecting nutrient loss Good study-review of different processing methods Are there factors about your home cooking or storage conditions , which may lead to unnecessary loss of nutrients?

The following points need to be clarified from the reading: ◼ Pasteurization methods can be either by "low-temperature- holding" (LTH) or "high-temperature-short-time" (HTST) treatments. ◼ Ultra-high-temperature (UHT) treatment is a pasteurization method ONLY if no aseptic packaging is used 18 Important note regarding heat treatments described in the assigned reading: “ Effects of food processing on nutritive values ”

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