17: Diet Forms and Formulations Flashcards
What is the quality of food related to? Why?
Not related to its form but to its formulation
Ingredient composition drives nutrient composition
Differences in ingredient selection process for formulation between dogs and cats
Dogs have more flexibility in ingredient selection and formulation. You can formulate an adequate diet without animal-based ingredients.
Cats are carnivorous and diet must contain a portion of animal-based ingredients. Significant amount of plant-based ingredients is possible, but vegetarian diets fed alone are not adequate.
Why must cat diets contain a portion of animal-based ingredients? (3)
- Increase acceptability by cat
- specific nutrients: arachidonic acid, taurine
- improve palatability
An ingredient has multiple characteristics related to…
- nutrient characteristics
- functional characteristics (affect on feces quality, skin/gut health)
- food processing characteristics
- taste
- colour (for person)
Following extrusion, what characteristics can be added to the kibble?
Extruded particles can be coated:
- fat, flavour
- palatability enhancers
When we talk about ‘extrusion quality,’ what might this mean?
Whether kibble stays together, is nutritionally sound after extrusion, looks good and tastes good
What factors affect the quality control of extrusion?
1 is ingredient characteristics
then equipment variables, conditioning, pre-processing, cooling and drying
Why are ingredient characteristics important in quality control of extrusion?
Ingredients must have binding capacity
Wheat has gluten = sticking capacity, corn has poorer
Food properties, density and starch gelatinization are impacted by… (3)
- precondition and extrusion
- retention time, temperature, pressure and moisture
- degree of cook
What is starch gelatinization and what does it do?
Extrusion process for starch
Opens the starch up and improves its digestibility and palatability
Slide 8
Extruder operation*
One problem associated with extrusion/starch gelatinization
Retrogradation
Creates a starch-lipid complex if you heat it up and cool it down too fast
Slows starch and lipid availability
Resistant starch cats can’t digest
e.g. amylose-lipid complex
Slide 9
Pet food categories
Dry:
1. Dry-extruded (10-12% moisture)
2. Semi-moist (25-35% moisture) ‘treats’
Canned: 74-78% moisture
Why do consumers prefer dry extruded?
Storage, option to buy in bulk
Slides 11,12
Nutrient content as fed vs 100% DM basis in dry, semi-moist and canned foods
Major, minor and other ingredients in dry extruded foods? They are marketed as…
Major (24-50%, with starch): cereal grains, grain by-products
Minor (5-25%, animal protein): animal by-products, etc
Marketed as: kibbles, meals, pellets, baked
Advantages and disadvantages of dry extruded
Advantages:
- ease of storage and feeding
- lower cost (one-third to one-half of canned)
- free choice feeding option
- abrasive effects reduces tarter build up
Disadv:
- lower palatability
- change of reduced nutrient content w improper heating
- restricted amounts of fat and energy, lower digestibility
^^ can be overcome by proper formulation and processing
How are baked pet foods produced?
Traditional means of dough formation, shape cutting, baking
Fats and oils rarely applied post-baking
In semi-moist, which two ingredients are added with the purpose of preventing/reducing water activity in the food?
- Humectants (sugar, NaCl, sorbate): bind water and reduce water activity improving shelf stability, preventing mold and microbial growth
- Stabilizers: polyhydric (propylene glycol), food grade acids (citric acid)
Why are water binders needed in semi-moist foods?
Reduce water activity by binding it
Without them, the treats would spoil (mold, microbial growth)
How are semi-moist foods sold? Dried?
Sold in low-moisture diffusion packaging, sealed pouches (to prevent moisture loss and changes in water activity)
No drying after extrusion
Advantages and disadvantages of semi-moist foods
Adv:
- can be sold in bags, do not require refrigeration
- can be fed free choice, can be sold in larger amounts
- can be fed as patties
Disadv:
- greater cost of manufacturing and shipping
- contain acidifiers to lower pH and prevent bacterial growth
- higher in sugar to improve taste
How are snacks/treats for pets produced? What is a characteristic about them?
Historically produced using traditional means (dough, shape cutting, oven baking)
Recently, using extrusion
There is no requirement for them to bear feeding directions, as they are not ‘complete and balanced’
Canned/wet food often contains more…. They have high…
More fresh or frozen meat, poultry, or fish and animal by-products; 25-75%
High energy densities
Advantages and disadvantages of canned/wet food
Adv: increased palatability (higher in protein and fat; easier to eat)
Disadv:
- generally, too much protein and fat (limited self control = obesity)
- greater cost, complex processing
- increased attention to dental care (not abrasive enough)
How is canned petfood processing complex? (explain the process)
Blending fat and meat ingredients + water + dry ingredients
Blended, ground to produce thick slurry
Heated to cook
Can, then sealed
Retorted (heat and pressure cooking and sterilization to destroy food-borne pathogens)
^ can lead to destructions of nutrients
Advantages of processing? (7)
- increased palatability and acceptability
- increased nutrient availability
- removes toxins, inhibitors
- increases shelf life and storage time
- improves texture, taste or appearance
- increases or decreases nutrient density
- flexibility for consumer
Disadvantages of processing
- decreases palatability and acceptability
- can decrease digestibility
- can accidentally introduce contaminants
- may reduce texture, taste and appearance
Examples of new pet food categories? Their popularity has more to do with…
- fresh (refrigerated)
- raw
- dehydrated
- freeze-dried
Anthropomorphism
Benefits and risks of raw pet food
Nutritional benefits:
- greater bioavailability of some nutrients (that would be heat damaged)
Infectious disease risks:
- greater risk of pathogenic bacteria (risk to pets and owners)
- heat can kill these bacteria