A Food Waste Solution You Might Not Know You Are Already Using

The Food Waste Solution That You Might Not Know You Are Using

Some of the bagged bread options in a local grocery store

Do you buy bagged bread in the grocery store?  There are usually several options including bread made with whole grains or containing several different kinds of grain. You have probably noticed that such breads stay nice and soft for quite a while.  Some people are even suspicious about that imagining that the bread might be “loaded with preservatives.”  They are not.  If you buy the freshly “baked in the store” options like baguettes, or get those at a bakery, they are really tasty, but they rather quickly become stale.  They become candidates for making French Toast or maybe croutons.  That kind of short-lived bread is amajor source of food waste and some have even found creative ways to collect stale bread from bakeries and turn it into beer. 

Fresh bread from in-store bakery

The bagged bread on the other hand can remain good and usable for a week or more.  If you don’t get through using the loaf for a long time it might get moldy, but in general each loaf can keep a family fed with morning toast or lunch sandwiches for quite a while. That didn’t used to be the case.  Back in the 1960s the bread aisle was restocked almost every day and you could buy “Day Old Bread” at a discount - but it wasn’t very good. 

So what changed?  It’s an interesting story that involves crystals and enzymes.  We think of stale bread as being “dried out,” but that isn’t the real issue. Staling occurs when the starch changes to a crystalline form in the finished bread. The solution to the food waste problem of stale bread is a type of enzyme called “amylase” that can modify the bread’s starches during baking and keep that crystalline structure from forming after the bread is baked. To unpack that, I’ll go into some background on enzymes and on starch.

OK, flash back to high school biology class.  Do you remember learning about enzymes?  Those are proteins and if you do the 23andme analysis of your DNA, a good deal of it codes for the enzymes that make your body function.  These very cool proteins “catalyze” chemical reactions, serving functions like digesting our food, or turning it into the energy that keeps us going.  There are also enzymes in our liver that protect of from certain toxins.

Bread is made from mostly wheat grains that contain starch.  Starch is a really big molecule that is a long and branched chain built from many units of the simple sugar glucose linked together. The reason that a wheat plant makes starch is so the germinating seed can use it as a source of energy to start growing a new wheat plant.  About 10,000 years ago, we humans started growing wheat as a crop and it has been a major source of our food since then.  We get both energy and protein from eating wheat.

When we eat bread, there is an enzyme in our saliva called amylase that starts breaking the starch into simple sugars and the process continues in our digestive system.  There is a similar enzyme in the wheat itself because that seed needs to be able to tap into the energy stored in the kernel when it starts to grow.  The yeast we add to make bread also has various enzymes including amylase and there are even more enzymes from various organisms in something like sourdough bread.  Bread “rises” because the wheat and yeast amylase enzymes make some of the starch into simple sugars that the yeast then ferments to grow.  In the process the yeast makes carbon dioxide gas that makes bubbles in the dough that make the bread rise.  So in the enjoyment of bread there are already three different kinds of amylase enzymes involved- from the wheat, from the yeast and later from ourselves.

But after the bread is baked, the starch that is still mostly undigested can “re-crystalize” into forms that make the bread taste “stale” to us.  We think of it as “dry” but that isn’t really the issue. It’s a texture thing based on those starch crystals. What the baking industry discovered in 1990 is that they could add a different kind of amylase enzyme to the dough that would control the starch in baked bread and slow down the formation of the crystalline structure that makes the bread taste/feel stale. 

So if you look at the ingredient list of the bread in the store, it could list “enzymes.”  The one that keeps the starch from crystallizing is an amylase. Not only does that reduce the amount of bread waste generated by stores and in customer’s homes, it also has dramatically reduced the number of trips that bread trucks need to make from the bakeries to the stores, thereby reducing the amount of CO2 released into the atmosphere

Note the Enzymes" in this bread ingredient label

When we eat the bread, that tiny amount of enzyme is just a protein that our own digestive enzymes easily break down into the amino acids that we need as a part of our diet. 

So the next time that you pull a loaf of supermarket bread out of your breadbox and find it still soft and tasty, you can appreciate this robust, enzyme solution to the food waste issue of stale bread!

(Note: I am writing this article as part of a partnership with the enzyme producing company, Novozymes. This gives me the time to delve into the technical details about specific enzymes and then try to explain those in ways that make sense to as many readers as possible)

The Productivity Of Organic Farming In The US: Mind The Gap

This warning from the London "Tube" could apply to organic farming

(This post originally appeared on Forbes 10/9/15)

The productivity of organic farming is typically lower than that of comparable “conventional” farms. This difference is sometimes debated, but a recent USDA survey of organic agriculture demonstrates that commercial organic in the U.S. has a significant yield gap.

I compared 2014 survey data from organic growers with overall agricultural yield statistics for that year on a crop by crop, state by state basis.  The picture that emerges is clear - organic yields are mostly lower. To have raised all U.S. crops as organic in 2014 would have required farming of one hundred nine million more acres of land. That is an area equivalent to all the parkland and wildland areas in the lower 48 states or 1.8 times as much as all the urban land in the nation. As of 2014 the reported acreage of organic cropland only represented 0.44% of the total, but if organic were to expand significantly, its lower land-use-efficiency would become problematic.  This is one of several reasons to question the assertion that organic farming is better for the environment.

The USDA conducted a detailed survey of organics in 2008 and then again in 2014. Information is collected about the number of farms, the acres of crops harvested, the production from those acres, and the value of what is sold.  The USDA also collects similar data every year for agriculture in general and makes it very accessible via Quick Stats.  It is interesting that they don’t publish any comparisons of these two data sets as they would be able to make comparisons on a county basis. By working with both USDA data resources I was able to find 370 good comparisons of organic and total data for the same crop in the same state and where the organic represented at least 20 acres.  That comparison set covers 80% of US crop acreage.

For 292 of those comparisons, the organic yields were lower (84% on an area basis).  There were 55 comparisons where organic yield was higher, but 89% of the higher yielding organic examples involved hay and silage crops rather than food crops. The organic yield gap is predominant for row crops, fruit crops and vegetables as can be seen in the graphs below.

The reasons for the gap vary with crop and geography.  In some cases the issue is the ability to meet periods of peak nutrient demand using only organic sources.  The issue can be competition from weeds because herbicides are generally lacking for organic.  In some cases its reflects higher yield loss to diseases and insects. Although organic farmers definitely use pesticides, the restriction to natural options can leave crops vulnerable to damage.

I’ve posted a much more detailed summary of this information on SCRIBD with the data at the state level.

There is some potential for artifacts within this data set.  If the proportion of irrigated and non-irrigated land differs between organic and conventional that would skew the data.  With lettuce and spinach it is likely that the organic is proportionally more in the “baby” category making yields appear dramatically lower.  But overall this window on farming is useful for understanding the current state of commercial organic production.  Since the supply of prime farmland is finite, and water is in short supply in places like California, resource-use-efficiency is an issue even at the current scale of organic (1.5 million cropland acres, 3.6 million including pasture and rangeland).

You are welcome to comment here and/or to email me at savage.sd@gmail.com. I'd be happy to share a data file with interested parties and to get feedback about where particular yield comparisons might be misleading.

A more detailed presentation is available at https://www.scribd.com/doc/283996769/The-Yield-Gap-For-Organic-Farming

Olives at Risk

A very old olive orchard I visited in the hills on the Greek island of Corfu

(originally posted on Forbes, 7/21/15)

This spring my family traveled in Italy and Greece where I became enchanted with their ubiquitous olive groves.  Many are on steep hillsides and some of the trees are extremely old with beautifully gnarled trunks.  I began to think I should try to grow an olive tree at home in the San Diego area.  Then I learned some sad news about olives – news that suggests that it will become a more scarce luxury food in the future.

Although olives are an ancient crop, expanding their supply to keep up with population growth has been difficult. If we compare the production of crops in the early 1960s with that 50 years later (2005-10) almost all have increased in total tonnage, but much of that increase has come through improved yields and not just more extensive planting (see table below).  (Table)

How the supply of some vegetable oils has changed over 50 years

Olives stand out among food oils in that all the increased supply has come from additional planting.  Global average yields are 20% lower than they were 50 years earlier. No wonder olive oil is expensive.

But now, olives in those picturesque groves in Southern Europe are threatened by a deadly disease.  It is apparently a new strain of a North American organism called Xylella fastidiosa. Strains of that pathogen cause diseases of various crops, but it is not known to affect olives in California. Somehow a new, olive-infecting strain of Xylella originated in Central America and traveled to Europe via an ornamental plant.  In Italy, the pathogen is being spread by the common spittle bug and is now killing trees in dramatic fashion.

 

Olives trees killed by Xylella. Image from Institute of Plant Virology Italy.

Thus olives in Italy join citrus in Florida and grapes in California as examples of crops in jeopardy because of the inadvertent, global movement of bacterial pathogens or the insects that vector them.  The grape infecting strain of Xylella was only a relatively minor issue for California grapes until a new insect vector, the Glassy Winged Sharpshooter, was transported into the state – again probably on an ornamental plant.  The disease thatis killing off Florida citrus, and threatening citrus from Texas to California, arrived on an ornamental plant from Asia with both the vector and the pathogen (do we see a trend here about the movement of exotic ornamental plants?).

Problems caused by moving plant pests around the world is nothing new.  The three-century delay in the arrival of the potato late blight pathogen allowed that New World crop to become a staple, only to be decimated leading to the Irish PotatoFamine of the 1800s.  Two pests spread from North American grape species nearly destroyed the European wine industry in the late 1800s.  It is said that the movement of coffee leaf rust from Africa to Java in the 1870s was the reason that the English had to switch to tea.  However now, with ever increasing global travel and trade, many more crops are at risk. 

Although it would not be a quick solution, genetic engineering might be a good option for the olive problem as it would be for citrus, grapes, potatoes and coffee.  Whether that will ever happen is, unfortunately, another question.  Apparently the 2015 olive crop inCalifornia is looking good.  Perhaps that will take some pressure off our demand for olive oil from Italy.  In any case, we should enjoy the luxury of olives before they become even less available.

You are welcome to comment here and/or to email me at savage.sd@gmail.com