We participate in the Oregon State U Food Science Camp for middle school students.
Part of the STEM [science technology engineering math] Academies@OSU Camps.
We teach about bread fermentations, yeast converting sugars to CO2 and ethanol, lactobacillus converting sugar to lactic and acetic acids, how the gluten in wheat can form films to trap the gas and allow the dough to rise. On the way we teach about flour composition, bread ingredients and their chemical functionalities, hydration, the relationships between enzymes and substrates [amylases on starch to produce maltose for the fermentation organisms]; gluten development, the gas laws and CO2’s declining solubility in the aqueous phase during baking which expands the gas bubbles and leads to the oven spring at the beginning of baking; and the effect of pH on Maillard browning using soft pretzels that they get to shape themselves..
All this is illustrated by hands on [in] activities: they experience the hydration and the increasing cohesiveness of the dough as they mix it with their own hands, they see their own hand mixed dough taken through to well-risen bread. They get to experience dough/gluten development in a different context with the pasta extruder, and more and more.
A great way to introduce kids to the relevance of science to their day to day lives: in our case chemistry physics biochemistry and biology in cereal food processing.
We were also fortunate to have Erik Fooladi from Volda University College in Norway to observe the fun: http://www.fooducation.org/
If you have not read his blog and you like what we do here: you should!
pH, colloidal calcium phosphate, aging, proteolysis, emulsification or its loss and their interactions lead to optimum melting qualities for cheeses. A module in this year’s food systems chemistry class.
This module was informed by this beautiful article “The beauty of milk at high magnification” by Miloslav Kalab, which is available on the Royal Microscopical Society website.
Of course accompanied by real sourdough wholegrain bread baked in out own research bakery.
“The Science of a Grilled Cheese Sandwich.”
by: Jennifer Kimmel
in: The Kitchen as Laboratory: Reflections on the Science of Food and Cooking
Edited by Cesar Vega, Job Ubbink, and Erik van der Linden
More from ACS, and appropriate to the New Year.
A video on the chemistry of champagne.
Here is a still of the figure from the JAFC paper
More fun about flavor chemistry here.
|50% barley flour pita: with help from Leslie Mackie of Macrina in Seattle. Leslie showcased some of her breads made with barley and gave her own workshop on her breads. Leslie’s bakery is extremely well regarded – Macrina was named one of the USA’s top 10 bakeries in 2011 by BON APPÉTIT
|Barley pretzels, getting ready for the lye [NaOH] dip.|
Eat your wholegrains: barley that is!
After a long hiatus the blog is being revitalized.
More molecules of the moment to come.
This is wheat I did with my weekend.
Pictures are courtesy of Meeghen at Breadsong who also makes a killer 80% rye bread that uses the a “scald” or porridge of pre-gelatinized rye flour as part of the process.
The breads come from the session I shared with Leslie Mackie of Macrina Bakeries Seattle on barley in breads.
Other than that I shared a long session on the science of breadmaking and grain and flour testing methods with Lee Glass MD, and Bread Baker’s Guild member.
More good news about coffee
American Chemical Society Press release 4th May 2011
“New evidence that caffeine is a healthful antioxidant in coffee”.
Is Caffeine a Good Scavenger of Oxygenated Free Radicals? Jorge Rafael Len-Carmona, & Annia Galano. The Journal of Physical Chemistry B, 2011, 115 (15), 4538-4546. [link]
Len-Carmona, & Galano note that caffeine [1,3,7-trimethylxanthine] is found also in “seeds, citrus fruits, olive oil, tea, and cocoa beverages“.
Their work suggested that caffeine is a good scavenger of some reactive oxygen species, but not all. Excellent •OH scavenging activity was reported, only “modest” scavenging of •OCH3 and no scavenging of HOO•
They cite work of others that suggest caffeine is effective against conditions related to oxidative stress in the body including Alzheimer’s disease, eye lens damage from photochemically induced reactive oxygen species, and that caffeine [actually its metabolites in humans] may have antioxidant potential at least that of ascorbic acid .
Typically the press release was a little less guarded than the paper: “Scientists are reporting an in-depth analysis of how the caffeine in coffee, tea, and other foods seems to protect against conditions such as Alzheimer’s disease and heart disease on the most fundamental levels.” “Annia Galano and Jorge Rafael León-Carmona describe evidence suggesting that coffee is one of the richest sources of healthful antioxidants in the average person’s diet. Some of the newest research points to caffeine (also present in tea, cocoa, and other foods) as the source of powerful antioxidant effects that may help protect people from Alzheimer’s and other diseases“.
Barley bread – first try
straight-dough process made with
90 parts whole-grain stone-milled STREAKER hull-less barley flour;
10 parts dry wheat gluten;
100 parts water
1.5 parts instant yeast
2 parts salt
1.5 part malted barley flour
mix till elastic
1 hour bulk fermentation
divide 650 g & shape
1hour final proof
bake 200 deg C [400 deg F] 35 minutes
Physical and Sensory Properties of All-Barley and All-Oat Breads with Additional Hydroxypropyl Methylcellulose (HPMC) β-Glucan. Yookyung Kim, Wallace H Yokoyama. Journal of Agricultural and Food Chemistry 2011 59 (2), 741-746
One of the short chain fatty acids produced in lower bowel microbial fermentation. Butyric acid production in the human lower gut is promoted by the ingestion of resistant starch [RS]: that is, starch that is resistant to digestion in the preceding elements of the digestive tract via either acidic or enzymatic hydrolysis. There are different types of RS:
RS1 is starch physically occluded [hidden] by other plant anatomical structures, e.g. when consuming unmilled whole grains;
RS2 is raw granular starch of poor digestibility often with B-type amylopectin crystal structures [potato & banana starches], RS2 starch becomes digestible on cooking after gelatinization;
RS3 is most commonly based on normal, or preferably high-amylose, starch sources. The need for amylose in RS3 is the enhanced capability of amylose to quickly and strongly re-crystallize (retrograde) on cooling of a cooked starch matrix. The strong tendency of amylose to re-crystallize and the ability to grow and make the amylose crystallites more perfect during repeated heating and cooling cycles is exploited in the food industry in order to create sources of RS3 for addition to foods
Back to butyric: the higher levels of butyric acid that arise from the RS fermentation (compared to the higher amount of propionic acid fermented from non-starch fiber sources) are believed to be the genesis of the protective effects of RS against colo-rectal cancers. Butyric acid is believed to act as a cell growth regulator for the cells in the bowel epithelium, but also contributes to other more general factors that improve bowel function such as lowered fecal pH. RS appears to be fermented in the distal (descending) colon, as opposed to non-starch fibers that are fermented in the ascending and transverse colons, it extends these beneficial attributes further along the digestive tract.