Science of Jello

1. Science of Jello http://www.gelatin.co.za/gltn1.html http://infohost.nmt.edu/~fuierer/Mate%20101L%20Posters/Jello%2520revised.pdf

2. Gelatin • Is a long molecule called a polymer (pure protein) • Poly is a Latin word that means 'many', • 'mer' is short form of “building block”

3. Polypeptide • Polypeptides are polymers in which every • third “mer” unit is a Glycine molecule • Poly=many • peptide= amino acid or protein

4. Gelatin is used in • marshmallows (gelatin is a foam stabilizer) • Yogurt; to make it thicker without draining to prevent syneresis (disintegrate with a lot of exuded water) • This allows yogurt with fruit containing products • pleasing shiny appearance meats such as canned hams, poultry • Gelatin can also be used in cheese manufacture to improve yield and in the stabilization of thickened cream.

5. Gelatin is used in • coats medicines to make them easier to swallow. • used to clarify beer after brewing. • in casinos to coat playing cards, • binds match heads together. • used in forensic science to simulate human tissue

6. “fining" applications; gelatin reacts with tannins and proteins in fruit juices forming a precipitate • which settles leaving a supernatant • This makes the juice stable so it does not cloud further formation with storage time. • Gelatin is used in dried soups to provide the appropriate mouth feel (viscosity) to the final product. Gelatin is used in

7. syneresis • If a gelled jelly is frozen, the product will suffer from syneresis and on thawing the clear jelly will release a large amount of water from the bonds of protein holding the water in.

8.  if water containing 0.5 % gelatin is frozen, the water will freeze as millions of small discrete crystals, instead of forming a single solid block of ice. • This effect is most desirable in "ice lollies" and is also used • in ice cream manufacture to obtain a smooth product with small ice crystals and also to ensure that any lactose precipitates as fine crystals avoiding the development of graininess with time

9. Emulsifyingproperties • The amphoteric character • (molecule or ion that can react as an acid as well as a base ) • as well as hydrophobic areas • (non-polar, repels water)

10. on the peptide chain gives gelatin limited emulsifying and emulsion stabilising properties used in the manufacture of toffees and water in oil emulsions like low fat margarine. • Emulsion- combination of 2 or more liquids that do not usually mix • Ex: oil and water

11. Gelatin is an amphoteric protein • with isoionic point between 5 and 9 • Isoionic is when the zwitterion has an equal number of positive and negative charges

12. Zwitterion • Positive and negative ions are apart and separated within the molecule • Common in amino acids and proteins

13. gelatin is not • a complete protein food because the essential amino acid tryptophan is missing and methionine is only present at a low level. • Complete protein means that it includes all 20 amino acids needed to make all the proteins in your body.

14. 20 amino acids

15. How is Jell-O Made? • In their natural form, polypeptides are crystallized, and are called collagen. • Polypeptides occur in the hides, bones, and connecting tissue of mammals.

16. In collagen, polypeptides have a triple helix which is similar in structure to DNA which is shaped as a double helix. • Collagen is not water soluble, so it needs to be modified to make gelatin

17. The first step in the manufacture of gelatin from collagen is to dissolve the collagen. • boiling in either a strong acid (Type A polypeptides) • or a strong base (Type B polypeptides) • Aged beef hides (old cows) are better for Type B • the polypeptide molecules are broken in a process called hydrolysis, and unraveled.

18. This is called thermaldenaturation of collagen • Type A or B are made differently to suit particular applications or uses.

19. The next step is to neutralize the solutions • Acid is added to the basic solutions, and base is added to the acidic solutions. • After this, Hot water is added, and all the stuff that shouldn't be in there …… • pig hair • bone chips, etc. • are filtered out. • The next step is to boil off as much water as possible, and then let it chill. • Then the Jell-O is dried and ground up.

20. What happens when I make Jell-O ? • dry gelatin swells or hydrates when stirred into water • Polypeptides are soluble in water at high temperatures (40C+), • but not at lower temperatures.

21. When a water solution of Jell-O is cooled, the molecules attempt to return to their triple helix state. • In order for one helix segment to grow, it must unravel another helix. • The final state is one in which molecules are frozen in place, in a configuration that they would prefer not to be. • The molecules form a loose network in three dimensions, filled with fluid;

22. if some of this fluid is removed, the network dries, and the gel shrinks. • If fluid is added, the network stretches, and the gel expands. It's not quite stable, • but it's not changing either so it is called 'metastable’

23. gelatin is usually available in granular powder form • although in Europe, sheet gelatin is still available.

24. forms thermally reversible gels with water, • gel melting temperature (<35°C) is below body temperature, • which gives gelatin products unique organoleptic properties • and flavor release

25. Organoleptic • A food that is experienced by the senses, • Such as taste, sight, smell, and touch.

26. If gelatin solutions are spray dried or drum dried from the sol state, the resulting gelatin is "cold water soluble" • A sol state is a colloidal suspension of solid particles (1-500 nanometres in size) in a liquid. • Examples include blood, pigmented ink, and paint.

27. such gelatins gel quickly when stirred into cold water. • These gels are generally not clear, so the use of this form of gelatin is limited to milk puddings and other products where solution clarity is not required

28. The disadvantage of gelatin • is that it is made from animal hide and bone (not from trotters as is a common perception) • pigskin, cow hide, fish skin and in China, donkey hide are used quite extensively

29. Kosher and Halal status and vegetarians have objections to its use. • Kosher is according to Jewish Law; • Non kosher would be food that is from nonkosher animals or from kosher animals that were not slaughtered in the ritually proper manner, • a mixture of meat and milk, wine, or grape juice (or their derivatives) produced without supervision, the use of produce from Israel that has not been tithed, or the use of non-kosher cooking utensils and machinery.

30. Halal is according to Islamic Law; • pork and all its products; 'animals improperly slaughtered'; alcoholic drinks, including all forms of intoxicants; carnivorous animals; birds of prey; and any food contaminated with any of these products.

31. Other vegetable based chemicals that can also gel are starch, alginate, pectin, agar, carrageenan etc. • but vegetable gels lack the melt in the mouth, • elastic properties of animal based gels

32. loss of gelatin solubility after storage • Can happen in a new kitchen cupboard • residual formaldehyde vapor from the adhesives used to make adhesives water-resistant • causes cross-linking of the gelatin so the strands cannot form or gel. • the "smokes" used in food preservation are rich in aldehydes and can have unwanted reactions with gelatin keeping the gel from forming

33. Often the cause of degradation or hydrolysis of gelatin in solution is microbial proliferation, so gelatin solutions should not be stored for longer than is absolutely necessary, and after addition of the acid to confectionery formulations, the solution should be used and cooled/gelled with minimal delays.

34. Gelatin • excellent nutrient for most bacteria, • hence the manufacturing processes have to carefully avoid contamination. • Most countries have microbiological specifications for gelatin, but generally they are not very onerous (hard).

35. Total mesophyllic(organism that grows in medium temperature) plate counts of 1000 are generally accepted with various countries limiting the presence of Coliforms, E. Coli, Salmonella, Clostridial spores, Staphylococci, and sometimes even Pseudomonades.

36. Generally Regarded as Safe (GRAS) • Gelatin is regarded as a food ingredient rather than an additive • and it is Generally Regarded as Safe (GRAS). • In 1993 the FDA reiterated the GRAS status of gelatin and stated that there was no objection to the use of gelatin from any source and any country provided that • the hide from animals showing signs of neurological disease were excluded and also • Specified Raw Materials were excluded from the manufacturing process

37. Although, at the beginning of the Bovine Spongiform Encephalopathy (BSE) scare in Europe the popular media brought suspicion on all products of bovine origin as being possible transmitters of the disease to humans as CJD, • this was a thoroughly unscientific assessment of the dangers of spreading infection.

38. It is now recognized that BSE is a neurological and brain problem and not associated with the hide of the animal.

39. It is also recognized that the processes of manufacturing gelatin make it virtually impossible for the survival of a defective prion, if it were present in the first place. • Prion; combination of 2 words- protein and infection, BUT no DNA, just a protein • untreatable and universally fatal. • Extremely resistant to heat and pressure, so hard to “sterilize” infected tissue to destroy the prion

40. Some raw fruits • like pineapple and papaya contain • proteolyticenzymes (protease) like bromelin • which hydrolyse(break with water) gelatin and destroy its gelling ability. • the fruit has to be cooked to destroy the protease before the fruit is added to gelatin solutions.