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Bch412 starch processing 1
- 2. Starch Composition • Amylose. • Linear α-1,4 glucose chain. • MW~106 . Branch approximately every 200 glucose units • Amylopectin. • Linear α-1,4 chain • with an α-1,6 branch approximately every 20 glucose units. • MW~108
- 5. Amaranth starch (Bar: 1 µm) Arrowroot starch (Bar: 20 µm) Buckwheat starch (Bar: 5 µm) Cassava starch (Bar: 10 µm) Corn starch (Bar: 10 µm) Oat starch (Bar: 5 µm) Potato starch (Bar: 50 µm) Rice starch (Bar: 2 µm) Kidney bean starch (Bar: 20 µm) Sources of starch
- 6. Processing • Three ways of processing – Water treatment – Enzyme treatment – Starch conversion
- 7. Water treatment • When treated with hot water, starch separate into 2 main fractions: – Amylose (Insoluble) – Amylopectin (Soluble)
- 8. Water treatment • Amylose – Insoluble in water – 10 -25% of mixture • Amylopectin – Soluble in water – 75 – 90% of mixtuer – Highly branched
- 9. Enzyme treatment • Enzymes α and β - amylases degrade amylose and amylopectin • α – amylases are endoglycosidase –Attacks both amylose and amylopectin along the α (1’–4’) bonds in the core • β – amylases are exoglycosidase –Removes maltose units from the reducing end • Amyloglucosidase (glucoamylase) removes glucose units from non reducing ends • Debranching enzyme hydrolysis α (1’–6’) bonds
- 10. Enzyme treatment •Products: –glucose, –maltose, –Dextrin: • polysaccharide with low mol. weight due to partial hydrolysis; • used in infant food, adhesives for stamps and envelopes
- 11. Starch conversion • Starch hydrolysis into glucose which is converted to corn syrup then to high fructose corn syrup • Process involves –Wet Milling Corn – Corn refining
- 12. Wet Milling Corn Corn Cleaned Steeping Steep water Wet corn Germ Grind Degerm Condensed Wash Oil Germ Corn bran Starch & Protein meal Ethanol Corn Corn gluten sweeteners meal Corn gluten feed
- 13. 13 Wet Milling Corn • Starch is hydrolysed to glucose units • Glucose units are converted to –corn syrup (glucose and fructose) –then to high fructose corn syrup • The process is performed on an industrial scale • glucose isomerase to convert glucose to fructose
- 14. Corn refining • Starch slurry is broken into glucose and converted to fructose through steps: – Starch gelatinization by cooking at >100⁰C – Liquefaction by digestion with α - amylase – Hydrolysis done by fungal glucoamylase to form glucose – Filteration – Concentration done by evaporator
- 15. Corn refining • Isomerization of glucose to fructose • Purification – HFCS consists of 55 % fructose or 42 % fructose • Packaging
- 16. High Fructose Corn Syrup
- 17. High Fructose Corn Syrup Sweetener made from corn Nearly identical in composition to table sugar Table sugar = 50% glucose and 50% fructose In US HFCS contains either 55% fructose and 45% glucose 42% fructose and 58% glucose
- 18. Why food manufacturers use HFCS? • Flavor enhancement for both sweet and spice flavors – Baked goods, fruit fillings, tomato products, canned fruit, beverages • Provides fermentable sugars – baked goods and yogurt • Enhances moisture control, retards spoilage, enhances texture and extends product freshness – Baked goods, granola, breakfast and cereal bars
- 19. Why food manufacturers use HFCS? • Protects the firm texture of canned fruits • Reduces freezer burn in frozen fruits – Has a lower freezing point • Provides greater stability than sucrose in acidic carbonated sodas
- 20. Which food products use HFCS? Examples: Baked goods Yogurt Spaghetti sauce Ketchup and condiments Salad dressing Beverages Granola Breakfast and cereal bars Canned and frozen fruit Frozen beverage concentrate
Editor's Notes
- High fructose corn syrup is a sweetener that is made from corn and used for many different functions in food products. Just as table sugar is made from sugar cane or beets, high fructose corn syrup is made from corn. HFCS is nearly identical in composition to table sugar which is approximately 50% fructose and 50% glucose. There are two different formulas used for HFCS, either 55% fructose and 45% glucose or 42% fructose and 58% glucose. The function of the HFCS determines which formula a food manufacturer would use. To understand more about HFCS, let’s take a look at the two components that HFCS contains: fructose and glucose. Glucose and fructose are both a monosaccharide which is the simplest form of sugar. You can think of these as the smallest building blocks for carbohydrates. Glucose is found in nearly all foods that contain carbohydrates and fructose is commonly found in fruits and honey. Like table sugar and other carbohydrates, HFCS has 4 calories of energy per gram.
- A common question about high fructose corn syrup is why would food manufacturers use this product? HFCS serves many functions in food and many of which do not necessarily make the product taste sweeter. HFCS can be used as a flavor enhancer for both sweet and spice flavors. For this function, manufacturers will use HFCS in products like baked goods, fruit fillings, tomato products, canned fruit, and beverages. HFCS also can provide fermentable sugars in food products such as baked goods or yogurt. Other functions HFCS serves are to enhance moisture control, retard spoilage or increase shelf life, enhance texture and extend freshness for such foods as baked goods, granola, or breakfast and cereal bars.
- In addition to it’s functions to enhance flavor, provide fermentable sugars and extend shelf life, HFCS also can be used to protect the firm texture of fruit in canned fruit products. HFCS reduces freezer burn in frozen fruit products due to having a lower freezing point than sucrose which serves a nice purpose in providing frozen beverage concentrates that are pourable straight from the freezer. Finally, HFCS also provides greater stability than sucrose when used in acidic carbonated sodas.
- Now that you’ve learned the functions of HFCS, here is a list of the food products that commonly contain this ingredient: baked goods, yogurt, spaghetti sauce, ketchup and condiments, salad dressing, beverages, granola, breakfast and cereal bars, canned and frozen fruit products, and frozen beverage concentrates.