Inspiration: The Kitchen Chemistry Sessions

Congratulations to Subha Ranjan Das an Assistant Professor in the Department of Chemistry @ Carnegie Mellon University


The Kitchen Chemistry Sessions


The taste of Chemistry

Lots of inspiration and resources available through these links

Chemistry in the Kitchen

a forum

The Kitchen Chemistry Sessions

A Facebook page

CMU’s Magazine

Our 2011 FST 425 “Bringing Food Chemistry to Life” pretzels ready for the acid, neutral, and pH 8, 10, and 14 dips.

My favorite food – bread

Great discussion of the bread-making process by award winning, erudite, and articulate baker Craig Ponsford. Craig is a past chairman of the board of  the Bread Bakers Guild of America and won the French and Specialty Breads category in the 1996 Coupe du Monde de la Boulangerie in France, the win helping to energize the artisan bread movement in the USA. Craig is incredibly generous of spirit as I have luckily come to know over the last year.

[Tom McMahon was the founder of the BBGA]

CRAIG’S “OBSESSIVES” VIDEO at Chow: a beautifully straight-forward exposé of the craft

Craig just opened a new place in San Rafael CA. PONSFORD’S PLACE. It’s worth visiting the website, but if you’re in the area visit the bakery.

You can also see Criag in action at making a whole-wheat ciabatta [formulation here].

On the theme of community grains keep your eyes out for the Kneading Conference West in the state of Washington September 2011, where if plans go right I will be presenting on formulating barley flour into hand-crafted breads. This is a new extension of the well regarded Kneading Conference in Maine. The barely work is part of our push to reintroduce barley as a mainstream food. The major partner in this is our barley breeding program led by Pat Hayes.

Other proponents of barley as food can be found at…


Both sites have info and recipes to help make barley a part of your day.

Why would you. Well apart from great taste it’s good for you.


A winter of food chemistry instruction

Can’t show the students for administrative reasons, but we had a good and educational time once again.

Bringing you highlights from the second iteration of  “BRINGING FOOD CHEMISTRY TO LIFE”.



Mayonnaise and egg white foams, and ways of messing them up that were instructive for the chemistry lesson.


Using the Brookfield viscometer to show how viscosity changes with molecular weight @ equivalent w/w concentration, and how it changes with w/w concentration @ equivalent molecular weight. The Brookfield with the helipath stand was also good for demonstrating how the viscosity of the mayonnaise decreased with increasing shear rate [shear thinning]. The helipath stand makes sure the sensor is going through an as yet unsheared region, taking time-dependent thixotropic behaviors largely out of play.

Fun with spherification whilst experiencing the gel forming capabilities of biopolymers with different gelling mechanisms [alginates, glucomannans, methylcellulose].

COFFEE WEEK: browning reactions, & foam and emulsion production and stability in espresso as related to roast degree [and therefore  the interplay between arabinogalactan peptide, and maybe galactomannan, extractability [during hot water extraction] and thermal degradation [during roasting] in determining the stability of the espresso crema]

Prepared for a cupping [monsooned, versus washed arabicas, versus robusta]

Color versus roast degree via tri-stimulus color meter.

How fun to have an espresso machine as part of the lab equipment! And coffee roasters too.

The instructor/barista hard at “work”

STARCH WEEK: not just formal viscometric studies, but also hands on experience of the different gelatinization temperatures and pasting behaviors of a variety of starches [e.g. potato versus wheat].

The instructor/starchista hard at work.

Using freshly made noodles as a way of bringing to life the profound  functional influence of differences in starch amylose content on food texture.

MEAT WEEK: As a plant scientist I find this work really hard to clean up because of all the fats!

Water holding capacity, gelation with salt and heat, transglutaminase, effect of pH and nitrites on color


Pretzel logic

Final lab session of our Food Chemistry class this year.

20100311 AR pretzel ANNOT

An experience of the effects of pH on browning reactions.

We make a variant of traditional soft pretzels, using a rather leaner formula than often used [for us no milk or eggs]. The loss of lactose from the milk and glucose from the egg might have contributed to our failure to get the same level of color development we saw last year when we used a full rich formula with egg and milk.

20090312 pretzels

Still it is a great way to experience the effect of pH shift on the color and aroma generated by primarily Maillard browning, allthough at pH 14 in the 4% NaOH, other reactions are very likely.

2010 formulation


2009 formulation

untitled 2009

A poolish is a 50:50 mixture of flour and water BY WEIGHT with about 0.1% of the flour weight as dried [instant] yeast [NO SALT] that is allowed to ferment around 16 hours before being added to the final dough.

Engaging students from the get-go

Starting a class today – Food Polymer Science for graduate students.

Getting students engaged is a challenge – even at this level (MS & PhD candidates) – some of them are only doing the course for required credits. So what can we do?

Mano Singham in Liberal Education** rails against the traditional “rule-infested, punitive, controlling syllabus that is handed out to students on the first day of class“, claiming that what is missing is any mention of learning and any indication of the passion of the instructor for the subject matter [we hope the instructor has some passion]. Our formal syllabi here at Oregon State U do list anticipated learning outcomes, but what is missing is the first person-narrative of the instructors view of the subject in the context of food production, consumption, and we hope, the enjoyment of our food.

The Center for Teaching and Learning here at OSU has a summer workshop on a “living course” – a guide to creating a partially web 2.0 based class delivery mechanism. A key part of the development of a living course/syllabus was to create a first person course narrative as a welcome to students and as a way of bringing the subject to life from the start.

I have linked to the current course narratives for both the graduate food polymers course as well as my science of deliciousness course for any of you food science instructors out there who are interested. Comments are welcome.



**Via TEACHING TIPS from the University of Hawaii’s Honolulu Community College.

Rye bread baked from a formula in Michel Suas’ “Advanced Bread and Pastry – A Professional Approach” from the San Francisco Baking Institute.

Open you fermentation horizons & mobile microscopy

A new post “Forays in Fermentation” from Jeremy at the Agricultural Biodiversity Weblog, via Research Blogging highlights two recent papers on fermentation that go beyond the usual beer/wine paradigm that I see in some students that choose our fermentation option.

The papers are

  1. Nout, M. (2009). Rich nutrition from the poorest – cereal fermentations in Africa and Asia Food Microbiology DOI: 10.1016/ []
  2. Poutanen, K., Flander, L., & Katina, K. (2009). Sourdough and cereal fermentation in a nutritional perspective Food Microbiology DOI: 10.1016/

We have used idli (rice & mung beans & a small amount of fenugreek) and injera (teff –  Eragrostis teff) as demonstration fermentations in the Topics in Fermentation – Science of Baking class. They are quite interesting. The idli ferment smells for all the world like yoghurt, apparently from a colonization of lactic producing bacteria. We kicked off our injera by chewing some of the grain and returning it to the mix, giving an inocculum of acid forming bacteria [better not done immediately after cleaning your teeth] and amylase from saliva to provide the two essentials – fermentable sugars and fermentation organisms.

The paper by Nout looks like a good read.

Microscopy comes to Web 2.0

I have been looking for ways to streamline our experience of viewing the diversity and behavior of starch granules outside the traditional transmission microscope exercise we have done in Food Chem labs – most students, and I, who don’t use microscopes everyday, often have trouble setting them up, and as an instructor, with multiple microscopes in a lab, I don’t know if students are seeing what te ought to be.

A new development in clinical microscopy…

Breslauer, D., Maamari, R., Switz, N., Lam, W., & Fletcher, D. (2009) Mobile Phone Based Clinical Microscopy for Global Health Applications. PLoS ONE, 4(7). DOI: 10.1371/journal.pone.0006320

for adaptation to a mobile phone (or I guess, my FlipCam) would let us all see a share our visions of starch granules, and share in real time the excitement [well, I am a food chemist] of seeing starch granules literally explode when we douse them with 1 normal hydroxide.

For more see Dan Gorelick’s post at Science Planet , which I also found via my RSS feed from Research Blogging.

Science outreach summer

So far this summer I have given two short workshops using wheat, flour, bread,  and baking as a way of bringing food chemistry to life.

The First group was the

Oregon Farm Bureau’s  Summer Agriculture Institute

on the theme of Grain-Gluten-and Great bread. And started with the quote from Henri Fabre a 19th C French entomologist.

“History celebrates the battlefields whereon we meet our death,
but scorns to speak of the plowed fields whereby we thrive;
it knows the names of kings’ bastards
but cannot tell us the origin of wheat”

We worked through H.E. Jacob’s “Rivalry of the grasses” from “6000 Years of Bread” on the theme that wheat was ascendant partly because it made risen products with palatable textures as a result of the unique properties of gluten proteins [their stubborn insolubility, the ability of the large glutenin molecules to cross-link into enormous (by molecular standards) elastic networks, and the viscous contribution of the gliadins leading to the viscoelasticity of wheat flour dough].

We looked at the fracture properties of grain during milling and how these are related to a single gene that determines if wheat kernels are soft or hard. Then through the genetics of gluten diversity and finally to experiencing some of this in breads and doughs. it was a lot of fun, and we had great bread to eat as well.




The Second Event was the…

Apprenticeships in Science & Engineering (ASE) Mid-Summer Conference

workshop for high school juniors and seniors.

This year we went with the TSoB (the science of baking) workshop again. But this time enhanced with hands-on dough mixing, and sprinkles of…

Polymer chemistry – dough and gluten properties
Physical chemistry – dough hydration and mixing
Physics/Rheology – fracture mechanics in milling, dough properties, bread texture
Organic chemistry – Maillard browning reactions
Physics – the gas laws & rising bread
Biochemistry – fermentation
& Genetics

All the students were remarkably engaged with the topic, helped along by a bribe of very fresh baguettes. The teachable moments were abundant but it seemed the most effective were;

-to experience the relationship between weak and strong dough and dough elasticity by rolling out dough  by hand.

-to hand mix a dough from scratch and to experience the rate of hydration and to feel gluten devlopment and to get to understand why we need air in dough (an aqueous phase saturated in CO2 cannot spontaneously create gas bubbles, they need to be prenucleated in the dough).

-to experience the relationship between water activity and crust browning.

We had a lot of fun and are looking forward to next year.

I don’t have clearance yet to show faces, but even the hands tell a great story about student engagement !

We have one more workshop planned this summer for the K-12 science and math teachers of Lincoln County Oregon.





Hopefully some food chemistry came to life…

There are many elements needed to create a good and compelling class – good material, a willing instructor, but the essential element is enthusiastic and dedicated students.  It is a circular argument: enthusiastic students generate enthusiasm in the instructor, which generates enthusiasm in the students, and around we go again.

I was privileged to have an almost uniquely good natured, good humored, and hard-working group who were willing to participate in this experiment in teaching food chemistry. Of course not everything that was tried worked flawlessly – but no good thing was ever perfect the first time around. And we were not having enough fun…

The key structural element of the class that I believe led to our moderate success was the use of case studies to highlight many of the basic elements of food chemistry. The two more successful ones were bread making and espresso.

Breadmaking was viewed as a system both in narrow and broad senses. In the narrow sense: a matrix of interacting components in the dough and in the finished product. In the broader sense; as the progress of a variable agricultural raw material through its intermediate processing steps (e.g. milling) through to final processing, storage, and consumption.

In the narrow sense we were able to incorporate elements of…

Polymer Science (entanglements, glassy and rubbery states and their responses to changing temperature and plasticization [water])

Rheology (viscoelasticity)

Starch behavior (gelatinization, susceptibility to attack by amylases, & retrogradation [junction zone nucleation and growth] and staling)

Maillard reactions (the effects of water activity, temperature, pH [mostly with the pretzel lab], and the contribution of fermentable reducing sugars from damaged starch)

Foams and foam stability (dough gas cells as a solid/liquid foam stabilized by proteins and lipid-based surface active components, the foam to sponge transition from dough to bread)

Enzymatic activity and thermostability (mostly amylases:  the increasing susceptibility to hydrolysis of undamaged and damaged starch granules and finally gelatinized starch; the different windows of opportunity for extensive hydrolysis of gelatinized starch during baking by fungal, cereal, and bacterial amylases )

In the broad sense we were able to observe elements of…

Genetics (the interaction with genetically determined kernel hardness and subsequent starch damage during milling, fermentable sugar production by amylases, and Maillard development of crust color; the genetics of gluten protein variability and its effects on gluten and dough viscoelasticity),

Rheology/Polymer science (fracture mechanics of kernels, polymer entaglements – stress build up and subsequent relaxations as vital steps in the transformation of flour, water, salt, and leavening [yeast or sourdough] to bread)

Espresso was also viewed in these two ways.


In the narrow sense we were able to incorporate elements of…

Rheology – the contribution of particulates to viscosity, the contribution of polymer size to viscosity and to the persistence of espresso crema as expressed by changes in foam drainage related to viscosity

Maillard (of course) – during roasting, the delay while the beans dry out, the increasing darkness, the formation of aromatic volatiles, the production of carbon dioxide, and the role of carbon dioxide in the formation of the cream foam.

Microstructures and inhomogeneity – the idea of espresso as a polyphasic colloidal system (e.g. Piazza, L; Gigli, J; Bulbarello, A (2008). Interfacial rheology study of espresso coffee foam structure and properties. Journal of Food Engineering 84 (3) 420-429. )

In the broad sense we were able to incorporate elements of…

The idea of coffee as an agricultural product; variability in composition related to species, region of growth, the fact that it needs intermediate processing before it can be roasted (allowing an opportunity to explore cell wall polysaccharides in detail  – particularly the pectin in the cherry mucilage).
Of course there was much more – but this is just a summary.

And of course student engagement is vital. The following pictures tell the story, and I need to express tremendous thanks the class for their collective contribution to a successful term !!!

Starch lab

Pretzel lab

Coffee day

Starch again

Meat lab

Baking lab