Diet Processing and Protein Digestion

Types of Diet Processing

• Maillard processing involves the carboxyl group of a carbohydrate reacting with the amino group of an amino acid, producing odors and flavors.
• Tannins protect proteins by making the plant less digestible.
• Formaldehyde preserves tissues using alpha-CH2 linkages.
• Acid treatment denatures proteins.
• Protected AA protect amino acids to ensure absorption in the small intestine.
• Trypsin inhibitors decrease digestibility (soybean).

Protein Digestion

• Protein digestion is essential
• PH drop leads to trypsinogen and chymotrypsinogen production.
• After activation through cleavage, intestinal walls produce peptidases.
• Polypeptides are split through peptidases.
  • They're transported into enterocytes that specialize in absorption.

Protein Absorption

• Most protein is absorbed in the jejunum and ileum as amino acids
• Nitrogen converts into ammonia.
• Ammonia is toxic; it is excreted from cells and sent to the liver.
  • It's converted to urea and water.

Carbohydrates

• Carbohydrates (CHO) are polyhydroxy (OH) aldehydes and ketones (C=O).
• They constitute about 2/3 of diets.
• Carbohydrates are major suppliers of energy, typically the cheapest source, and are abundant in plants.
• A diet can consist of 70% carbohydrates.
• "Too much glucose is bad."

Monosaccharides and Disaccharides

• Pentoses and hexoses are monosaccharides.
  • Xylose (pentose) is a component of hemicellulose.
  • Hexose includes glucose, galactose, fructose, and mannose.
• Disaccharides are connected by a glycosidic bond.
  • Sucrose is fructose and glucose.
  • Lactose is glucose and galactose.
  • Maltose is glucose and glucose.
  • Cellulobiose is glucose and glucose.
• Has B1-4 linkages but is glucose dimer
• Maltose and cellulobiose differ by where the bond connects.

Polysaccharides

• Polysaccharides include compounds with alpha 1-4 or 1-6 linkages.
  • Alpha linked polysaccharides are not straight chain molecules
• Amylose is a glucose polymer with alpha 1-4 linkages.
• Amylopectin is a glucose polymer with alpha 1-4 and alpha 1-6 linkages.
• Glycogen animal version of amylopectin (branched chained glucose polymer).
• Cellulose is a straight chain glucose polymer with Beta 1-4 linkages.
• Animal enzymes hydrolyze alpha 1-4 but not beta linkages.
• Microbes can digest fiber because they have enzymes that break B 1-4 linkages.
• Cellobiose is a glucose dimer with B 1-4 linkages, it isn’t a polysaccharide

Hemicellulose

• Hemicellulose is composed of 5 and 6 carbon sugars and uronic acid in polymeric form
• Hemicellulose is HETEROGENOUS
• Hemicellulose is often associated with lignin.

Pectin

• Pectin is a polysaccharide rich in galactouronic acid, rich in alpha 1-4 linkages.
• It's similar to hemicellulose but less lignified and more digestible.
• The alpha 1-4 linkages means MORE digestible.

Major Carbs

• Cereal grains have starch that provide when broken to glucose.
• Forages include cellulose and hemicellulose.

Lignin

• Lignin is heterogenous, as a plant ages, more lignin is produced.
• Lignin provides structural stability and reduces digestibility.

Primary and Secondary Cell Walls

• Plants have both primary and secondary cell walls.
• Primary cell wall is thinner and contains pectins and hemicellulose.
• Secondary cell wall is thicker and mainly cellulose.
• The middle laminate between cells provides strength to the plant skeleton.
  • Middle laminate contains 70% lignin.

Crude Fiber (CF)

• Crude Fiber (CF) Limitations:
  • Acts as though ALL fiber components are uniformly digestible. Ex: a diet high in lignin and low in fiber will have SOME crude fiber as low lignin and high fiber Ruminants can utilize cellulose and hemicellulose but lignin is considered indigestible
  • Not all lignin and hemicellulose is recovered in this method.
  • Can be included in the NFE (nitrogen-free extract)

Van Soest Method

• NDS: Neutral-detergent solubles consists mainly of lipids, sugars, starches, pectins, proteins and NPN with a digestibility of around 98%
• NDF: Neutral-detergent fiber consists of cellulose, hemicellulose, lignin. NDF: 100-NDS
• ADF Analysis: Residue contains cellulose and lignin
• NDF-ADF=hemicellulose

Corn Grain

• The components of corn grain:
  • Endosperm (85% starch, 12% protein).
  • Germ (85% of oil found here).
  • Pericarp (mostly non-starch CHO).

What is the difference between carbohydrate digestion in non-ruminants and ruminants?

• Non-ruminants digestion: -Digestion occurs minimally in the mouth -No digestion occurs in the stomach -There is extensive digestion in the small intestine
• Ruminants digestion: -Digestion does not occur in the mouth -No digestion occurs the stomach -Fermentation occurs in the rumen -Extensive Digestion occurs in the Small intestine

What are the conditions of a happy rumen

• Temperature of 38 to 39 degrees Celcius
• There is a constant food suply
• Continuos removal of fermentation end products
• PH must at about 5.5 to 7
• Constant mixing
• Needs to have constant osmotic pressure

Rumen Microorganisms

• In the Rumen bateria is predominant
• Protozoa it is larger than bacteria but less abundant
• There is Minor role for fungi
• Animals are born without bacteria, protozoa or fungi in GL tract. That is why protozoa-free ruminants can be created by Isolating a newborn immediately after birth!

Glycolysis Main Takeaway

• Takeaway from Glycolysis: One mole of glucose is degraded to two mole of pyruvate

What is a Lipid

• Lipids can be discribed as Hydriphobic, Organic compound that contains CARBON, HYdROGEN, and OXYGEN
• The Ratio of carbon to oxygen is greater in lipids than in carbohydrates and proteins
• Lipids contain 2.25X energy than carbohydrates and proteins
• Lipids can be referred to as Hydrophobic, Organic compound that is made of CARBON, HYdROGEN, and OXYGEN

Important Lipids

• Triglycerides have three fatty acids attached to ester linkages to a glycerol

  • They are a Major storage form
  • Important Glycolpids are commonly found in forages
  • High in C18:3
  • 1 fatty acid replaced by galactose

• Phosopholipids

  • They are found in microbial Lipids
  • Help makes uo the Cell membrane

• It has Hiigh in C18:2

• Lecithin has an Amphipathic molecule used to emulsity fat

Types of lipids

• Lipids of glycerol based include of Simple like lipoproteins - fats& oils -Compound like Glycolipids& Galactolipids and Non-Glycerol Based like Sphingnolipids - Glycolids - Cerebrosides - Terpenes and Eicosanoids

Structure of Fatty Acids

• Carbon chains ranging from 2 to 24 C in length.
• Very significant carboxyl group R-COOH
• Is WATER SOLUBLE
  • That is important
• Acetic Acid is created from H3CCOOH
• Propionic Acid is created from H3CCH2COOH
• Butyric Acid is created from H3CCH2CH2COOH ,

Fatty Acid Structure

• Saturated fatty structures have a straight chains with only a single C-C bond.
  • The fat is completely hydrogenated
  • Commonly found in animal Fats and they are more common in Butter
• Unsaturated fatty structures have branched/ straight chain.
  • Includes a carbon doubled bonds
  • Commonly found in Plants and they are more in Avocado Oil

Fatty Acid Conformation

• CIS-Unsaturated FA:
  • Are naturally occurring FA
  • Results in bent chains
  • Restricts the FA , making them less flexible TRANS Unsaturated FA
  • This is the result of human processing -Causes straight chains
  • More easily targeted by lipase -Which Can potentially affect biological processes

Conjugated Linoleic Acid (CLA)

• Between 2 doubled bonds ther's one single bond (double-single-double)
• Formed in microbial fermentation, adipose, liver, mammary gland this results in Insulin resistance
• If there's Cis-9, trans-11-CLA this results in Anti-carcinogen
• Can potentially increase blood good cholesterol
• If Trans-10, cis-12-CLA this results Type II diabetes, do not cause Type II diabetes