hello everyone welcome back to our Channel fot take Insight this video is a continuation of our carbohydrate Series in this video we are going to understand the very important topic in carbohydrate that is gelatinization and retrogradation in our previous video that is the part one and part two I have explained about a basic of carbohydrate and a part of functional properties of car carbohydrate I request you to kindly go through it for a better understanding of this video so let's begin with the gelatinization of starch so previously also I have explained regarding the starch molecules but in this video I'll just go in depth of this about the structure also so the starch is a major component of many food plants such as wheat barley rice corn potato sweet potato C Sawa Etc so it's a major source of carbohydrate and energy in the human diet starch consist of Amo and Branch amop pectin in previous video I've explained the structure and the bond between this and this molecules present in a ratio of around 15 to 25% is the Amo and the 85 to 75% is the amop pactin so the Amo here you can see it's a lean uh linkage of the alpha glucose unit and the bonding will be 14 glycosidic Bond whereas in amylopectin a linear will be there with the branch one where it will be one six glycosidic Bond so before studying the gelatinization we have to study the starch structure so the starch granule structure is organized in a ringed structure you can see this picture and uh this area is the emmer face area or less crystalline area so this granules it's a regular orientation of amorphus and crystalline reason that give the granules it characteristics by fren pattern so this is the pattern it's like a amerus it's a crystalline then amerus region crystalline amerus region this pattern it is um oriented in this pattern so the non crystalline or the amorphus reason this contain the Amo molecules and portion of amylopectin molecules so absorb water when we provide water for a gelatinization process so the water will be absorbed in amorphous area and then it will start rather freely moving freely within the granules so this is a pictorial point of a process of gelatinization I'll explain it further but a small little bit of expl explation in this picture this is a cross-section of a starch granule we can see the pattern here they have highlighted it and this pattern is like amerus crystalline amus crystaline so the absorption of water will be at this amerus region okay and then when we add water to it then uh the swelling or further I'll explain that the swelling of these granules will occur and this structure of the starch is composed of amylopectin and Amo where amilos you can see this is the linear one but if you are keeping it as a branch then this process this point will be a amop pactin so let's start with uh now the topic gelatinization so gelatinization is the breakdown of intermolecular bonds between starch molecules that is the breakdown of Amo and amop pactin bonding allowing the hydrogen bond sides to engage more water molecules the intermolecular Association might take place Place between o6 of the Amo and O2 of the amop ptin molecules due to the hydrogen bonding you can see in this picture the bondings here so when there is water and heat the intermolecular bond between starch molecules tends to break that's the like this o6 O2 Bond will start breaking and this when the hydrogen bonding site will have the ability to hold more water molecules in this side so the starch granules become dissolved in water and it will be irreversibly processed and it will act as a plasticizer so the process of gelatinization occurs in three steps starch granual swelling it's melting and Amo leeching so when we hit the star sample the swelling occurs due to the absorption of water into the amorphous space of starch where which I have explained previously therea the water enters tightly bound areas of star G that is after it will absorb in the Amor first days it will try to uh go towards the uh I mean crystalline um crystalline area which contain helical structure of amop actine normally water cannot enter this region but when you heat it allows that then the penetration of water increases the randomness of starch granules which leads to dis disintegration of the starch there are some factors which are involved in uh gelatinization the first is the type of the plant from which the starch is obtained the amount of water present in the medium even the pH plays a role in gelatinization process and of course the concentration of salt in the medium sugar protein fat contains so when any other ingredient contain within a starch can affect the gelatinization process like it may slow down the rate at which water is absorbed so let's take an example of a sauce like a pasta sauce where we use a flour for as a base so if a sauce contains sugar this sugar will try to absorb the liquid and are competing with that starch so this can disrupt and slow down the process meaning it will take longer time for the stars to thicken the sauce and if we are adding extreme or that is the too much sugar it can completely prevent the gelatinization process this is a small pictorial explanation this is a normal water and a starge granules are present so it first it won't get dissolved because the water temperature is a normal ambient temperature when we start heating it will lead to swelling of this starge granules and further if a temperature will increase to for more than 60° C the disintegration of the starch granules will occur and the amilos and the amop pactin which have been broken the Amo will come out will try to leech out here and then further it will get dissolved and we make the liquid thicken or the viscous a small representation of the star transation this is the starge Gran intact with the Amo and amop pactin so when we'll provide water after after heating this dentation will happen the Amo will come bleach out and the water molecules these are the water molecules it will come inside the next is the retrogradation of this starge so retrogradation I will say it's a opposite of gelatinization process in a mechanism I'm telling so retrogradation will occer after gelatinization process so retrogradation is a chemical reaction that takes place when Amo and amylopectin chains in cooked gelatinized starch realign thems when cooling the starch sample so in simple I'll explain this is the gelatinization process where the Amo have been uh leeched out from the starch granules so when we'll cool it and store it this amilos will come will try to enter inside and will try to realign with the other Amo being inside present and try to reign in a parallel form and the water molecules will start to leech out so this is the retrogradation of the starch so if we heat the starch and dissolve it in water it cause the destruction of the Cline structure of the Amo and the amop amylopectin molecules will lead to hydration and forms a viscous solution so if we cool this viscous solution or leave it at a low temperature the linear molecules and the linear part of amylopectin molecules t to retrograde and rearrange themselves again forming a more crystalline structure so the linear part of the molecules tend to place themsel in a parallel manner I have explained before that it will start uh arranging themsel in a parallel Manner and forming a hydrogen Bridges between them in this process we can observe that Amo crystallization is faster than aecting crystallization furthermore retrogradation cause the expel of water which can also be known as syesis so however when we can observe a small and amount of water on the top of the gel this retroration Pro process is directly related to staling or aing of bread so moreover retrograd starch is less digestible however the chemical modification of starch can lead to reduction or enhancement of the retrogradation process and these additives like fat glucose sodium nitrate Etc can reduce the ret retrogradation process of starch this you can see starch retrogradation in bread and rice grain this a very common this is the starch molecules when we'll heat and provide water it will gelatinize M structure will start absorbing water and once it is cool or stored for a long time the retrogradation will occur recrystallization will try to occur but U it will lead to a Stell bread and similar in the raw rice you can see here gelatin and then cooked rice Plus cooled then it will try to realign themsel and then it will uh the retrogradation of the starch will occur so let's see the basic like difference between gelatinization and ration so in definition gelatinization is the process of breaking down intermolecular bonds between starch molecules allowing the hydrogen bonding side to engage more water molecules whereas retrogradation is the chemical reaction that explain when Amo and amylopectin chaining cook gelatin starch deign thems when cooling the starch sample so here we have to provide Heat and the temperature here we have to cool it means we have to reduce the temperature here will be the leeching out here will be the uh realigning of the uh Amo and amitin structure the main concern here is water is taken into the hydrogen bonding site and here water is expelled from the polymer Network it forms a less crystalline structure it forms a more crystalline structure because here the breakdown of this starch like the starch disintegration OCC so the crystallinity will be less but in retrogradation it will be more it will be an Amo and am sorry amoros and the Amo and am amop molecules align to form a crystalline structure having hydrogen bond Bridges and the key difference between gelation and rogation is that gelatinization refers to the act of making or becoming a gelatinize whereas refer to Motion in a retrograde manner with this I end this video uh thank you if you have any query uh do comment us on foottech inside gmail.com [Music] you