יום שבת, 26 בינואר 2008

Gelufuction Process


Gelation of proteins is important to give food products, such as yoghurt-desserts, desirable textures. On an industrial scale, gelation is often induced by heating the final product. This has three main disadvantages. Firstly, sub-optimal uses of protein-ingredients since not all proteins (usually between 50 and 80 per cent) form aggregates that contribute to the gel strength. Secondly, the final texture is hard to predict and control and finally, delicate flavours are heated and sometimes destroyed. The cold gelation method that is based on separating the protein aggregation (heat) and gelation steps that are intertwined in traditional heat-set gels.

Moshik cookingChef:

Molecular khniocy- clicks on video icon.

וידיאו במטבח החדש/ השף מושיק

Chef: Jonnie Bour

Molecular Gastronomy- click on video icon

Aggregation is induced in a pre-heating step that makes it possible to fully denature the protein ingredient before gelation sets in. This ensures that all of the protein - more than 95 per cent - contributes to the gel. Gradual acidification of the solution of aggregates to form a gel at ambient temperature comprises the second step of the cold gelation method. A large part of the research has focused on the relations between the properties of the protein-aggregates and the mechanical properties of the gels. One important conclusion, , that allow formation of disulphide bonds during the second acidification step, is of crucial importance for the final gel hardness. Finally, heat-sensitive flavour compounds can now be added to a solution that does not require additional heating to form product in which the final gel properties can be precisely controlled. Food manufacturers can use the cold gelation method for dairy products such as yoghurt desserts, or processed fish such as surimi, and for the encapsulation of probiotics.

PH-Induced cold gelatin of whey proteins is a two-step process. After protein aggregates have been prepared by heat treatment, gelatin is established at ambient temperature by gradually lowering the pH. To demonstrate the importance of electrostatic interactions between aggregates during this latter process; -lacto globulin aggregates with a decreased is-electric point were prepared via succinylation of primary amino groups. The kinetics of pH-induced gelatin was affected significantly, with the pH gelatin curves shifting to lower pH after succinylation. With increasing modification, the pH of gelatin decreased to about 2.5. In contrast, unmodified aggregates gel around pH 5. Increasing the is-electric point of -lacto globulin via methylation of carboxylic acid groups resulted in gelatin at more alkaline pH values. Comparable results were obtained with whey protein isolate. At low pH disulfide cross-links between modified aggregates were not formed after gelatin and the gels displayed both syneresis and spontaneous gel fracture, in this way resembling the morphology of previously characterized thiol-blocked whey protein isolate gels Our results clearly demonstrate the importance of the net electric charge of the aggregates during pH-induced gelatin. In addition, the absence of disulfide bond formation between aggregates during low-pH gelatin was demonstrated with the modified aggregates. Keywords: -lacto globulin; whey protein isolate; chemical modification; aggregation/gelatin; electrostatic interactions; disulfide bonds

The mechanism of pectin gelatin depends on the degree of methoxylation. High methoxyl pectin gels due to hydrophobic interactions and hydrogen bonding between pectin molecules. Low methoxyl pectin forms gels in the presence of di- and polyvalent cations which cross link and neutralise the negative charges of the pectin molecule. Monovalent cations normally do not lead to gel formation with high methoxyl pectin solutions free of divalent cations, especially Ca. The present study found that alkali (NaOH or KOH) added to high methoxyl pectin leads to gel formation in a concentration-depended manner. It was also found that monovalent cations (Na and K) induce gelation of low methoxyl pectin and the time required for gel formation (setting time) depends on the cation concentration. The results indicate that a combined charge neutralisation and ionic strength effect is responsible for the monovalent cation-induced gelation of pectin.

This investigated the effect of a number of commercial-grade ingredients, either polysaccharides (wheat starch, corn starch and dextrin's) or with high protein content (gluten and dried egg), on the viscous and dynamic viscoelastic behaviour of a batter containing methylcellulose (MC) employed in a process that does not require a pre-frying step. Replacing part of the wheat flour present in a reference batter formula with either gluten or dried egg yielded an increase in the actual concentration of protein material, which resulted in batters that exhibited more marked shear-thinning behaviour at 15 °C. Conversely, the consistency of batters dropped when wheat flour was partially replaced with either wheat starch or modified corn starch, probably due to the ‘dilution’ effect of the polysaccharidic material on the wheat flour proteins which, in practice, form the network responsible for viscosity development in the batters studied at 15 °C.

A similar approach is used to explain the dynamic viscoelastic results at 15 °C. The storage and loss module both increased upon adding protein ingredients but decreased when some of the polysaccharide ingredients partially replaced the wheat flour. However, at 60 °C the opposite tendency was observed, since both viscoelastic module decreased in protein-enriched batters as a consequence of the disruption of starch gelatinization. On the other hand, both storage and loss module were observed to be higher in batters where wheat flour was partially replaced by native wheat starch or corn starch, which were already beginning to gelatinize at 60 °C.

The characteristic gelling pattern of MC, which is the key component to avoid the pre-frying step, was practically unaffected by the ingredients studied.

Finally, the thermo reversibility of the gelation process after a sudden increase in temperature up to 45, 60 or 80 °C, was progressively less evident as the final temperature increased. This is attributed to the fact that gelatinized starch reinforced the batter structure to a greater degree as the temperature was raised.

יום שני, 21 בינואר 2008

A Yang Chef succed at Frcenh three ASTRS


Culinary Arts is dedicated to the meaningful learning and excellent teaching that enables the cook's to achieve their full potential in cooking, dietetics and food service industries. On long term goal is to empower cook's to become leading partners in a dynamic prosperous community.

"Cooking is a new adventure every day. It's all about passion. You can teach people to cook, but you can't teach passion," he advised. "Put yourself into every dish you make."

To day the Culinary Institute's use the most modern equipment and proven teaching methods are two important elements of our primary goal: To provide the finest culinary education available to those seeking a career in Culinary Arts.

The application process for admission is a process the Culinary Institute is very proud of, as it guarantees the selection of only the best applicants for admission. Due to the cyclical nature of the industry.

What projects do you have on? Many. Probably the most exciting thing I’m doing right now is. Continuator aimed at of the French three ASTRE cook Jean-Georges Small of the French top restaurant L'Amsbourg in Baerenthal Elzas.Chef Moshik Roth, the owner of ASTRE Restaurant t Brouwerskolkje in Overveen in Nederland. He considers them selves on the future. Which confirm especially confessed state in our country for its knowledge of the molecular kitchen? Moshik and Jean Georges are good friends Moshik are find regular in the kitchen of small in Baerenthal. On his free days two times per month. Jean considers me as a continuator, Jean say he is my culinary father, I learn as lot of him. Moshik: My cooperation with Jean-Georges small is none secret more. I come there now already a year regularly concerning the floor.Moshik feel themselves gaveled that small him sees as aimed at a continuator. Provisionally he remains in the Netherlands. When it an adoption or very far-reaching cooperation reaches, we let us be according to Moshik years further. Culinary Institute is part of the Career Education Corporation network. Career Education Corporation is pleased to make placement assistance available for our graduates and alumni. With global access to candidates and job opportunities from our domestic and international sites, the culinary located on many of our campuses and can aid in securing employment that is both exciting and rewarding.

A cook work along with their Admissions Representative to determine which start date would be optimal for the cook. Although there is no set deadline for submitting application, The Culinary Institute does limit its enrollment, so you are advised to apply as early as possible to ensure full consideration.

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Moshik philosophy idea: Well, the concerns are different in each of them, but the objective in all of them is to achieve a comfort level between the cook/artist/performer and the customer/viewer/diner. And if we can achieve that, and the customers are happy and the cooks are happy, then we have a great experience. But if neither of the two parties are happy, then you have a closed restaurant. And if only one of the two groups is happy, you have one that will close. So, to create an opportunity for both the customers and the staff to have a superior experience is my constant struggle.

Moshik think people overestimate that. What I’m doing is taking a lot of the local ingredients we have available in Holland. I’m just using them in different ways than chefs are using them. My basic cousin is depending on Molecular Gastronomy. I have chosen a more populist vernacular. I think Mediterranean/French food is easier to like and love and less intimidating than most. So people overestimate my contribution, not in a bad way or a good way. It’s just that my food is simpler than a lot of other chefs’ food, and that makes it more accessible, and possibly easier to eat.

The ideas come from classic cooking, or any European culture, for that matter. As far as something like the offal menu, Europeans would definitely not throw anything away, and the use of the head or the liver or the kidneys is part of their quotidian experience. People were ready for it; they were tired of eating things they could easily make at home. When I go out to a restaurant I definitely order dishes that I know take either a long time to make or are difficult to source. Unless it’s a really special steak, there’s no reason for me to go out and eat that.

Dues the nature food changed in the last decade? Yes, for good or for bad, even the most classic Restaurants have been introducing non-traditional ingredients. And in some cases that’s good, because there should be no fear of new ingredients, and things can be redone or rediscovered in a better way. So they’re reinventing to avoid palate exhaustion. Chefs feel that to be fascinating and fun, they need to bring in new things. They’re looking to challenge their customers. I don’t have a problem with change.

I would like to think that. At this point in my career it’s very hard for me to turn down opportunities that I think are auspicious. I like things that are fun and I look to do them a lot, and that I have the opportunities to do them makes me a lucky guy. So, as busy as my schedule looks, I don’t ever wake up and say “Oh, crap, I got to do that.” I’m lucky that it’s worked out that way. But it is busy!

Produce---vegetables---are the most exciting thing to me. The constant evolution of the greenmarket-chef relationship is something that makes it very exciting to work in a restaurant kitchen and see what comes through.