1 day ago
|Part V: Is High Brix Enough? |
by Michael Astera
edited March 14, 2010
Finally the concept of measuring produce quality in degrees Brix (*Brix) is getting some legs. People like the idea of being able to determine quality in their food. Measuring Brix also has some fun geek-appeal, e.g. carrying a scientific instrument in your purse or pocket that can graphically show the difference between a sweet orange and one not worth tasting. When Chefs de Cuisine start meeting food deliveries at the back door with a refractometer in hand, the game changes. When the shopper at the local fruit stand pulls out a refractometer, the game really changes. It's no longer just about having pretty produce. Two green peppers may look identically perfect, but the pepper that "Brixes" 12 is likely going to taste like a green pepper; the one that Brixes 4 is only going to look like the real thing.
Does that mean that a crop that has a high reading in *Brix is high in nutrients? Probably, but which nutrients and in what form? Are those nutrients in the best proportion and amounts for human and animal health? Maybe, maybe not.
The Brix scale was invented to measure sugar content, and is scaled against the equivalent in pure sucrose dissolved in pure water, i.e. if the solution is 32% pure sucrose by weight, it reads 32*Brix. Except: A refractometer measures all dissolved solids that bend incoming light. Caribbean sea water from the beach out front measures 4.8*Brix.
What do other common items measure in *Brix?
Without exceeding my normal science budget, I managed to put together the following "Laboratory Experiment" yesterday:
Laboratory Experiment #1
The boxy thing at the back of the scene is an old worn out car battery. The sulfuric acid in its cells measured 13.2*Brix.
Lined up in front of it, L to R, are a couple of bags of commercial fertilizer, a glass espresso cup with silver spoon, a cake of papelon raw sugar, a 0-32*Brix refractometer, an orange and a banana. Behind, R to L, a box of baking soda, bottle of soy sauce, jar of salt, vanilla extract, refined sugar, and a bottle of Old Tom gin. On top of the battery, L to R, toilet bowl cleaner, phosphoric acid, and ceramic tile cleaner with ammonia.
I spent the late morning and early afternoon taking a *Brix reading of everything in the photo.
The dry items were mixed to saturation with local bottled water (0*Brix) in the glass espresso cup, then sucked up with a plastic pipette and a few drops of the solution were placed on the refractometer prism.
The household chemicals and other liquids were taken up directly from their containers using the suction pipette.
All utensils and the refractometer were carefully washed and dried between tests.
The refractometer was then held up to a good light source (the sky) and the reading in *Brix was noted.
Here are the results:
It is clear that the refractometer measures a lot more than sugars; these results indicate that acids and alkalies raise the brix reading, as does alcohol content. Pure chemical fertilizers also raise the Brix.
It is safe enough to assume that high-Brix produce will have more dissolved solids, but which solids?
Even if we just look at the sugars there can be a lot of variation in nutritional quality. What are the sugars likely to be in hybrid super-sweet corn? Simple sugars. High fructose corn sugar is about as simple as one can get.
Simple sugars metabolize quickly, give a big sugar rush, and cause an insulin spike; they are hyperglycemic. Long chain complex sugars, aka polysaccharides, metabolize slowly; they have a low glycemic index. The longer and more complex the saccharide, the slower it will be digested or metabolized.
Extremely long chain poly-saccharides are called muco-polysaccharides because they have mucus-like slimy qualities. Examples can be found in the sap of aloe vera and other succulents, comfrey, and slippery elm bark.
Note that aloe vera, comfrey, and slippery elm are all well-known healing plants. It is largely their muco-polysaccharide long-chain sugars that give them their healing qualities. These "sugar molecules" can have 30,000 or more individual sugar molecules "chained together", versus only two sugar molecules, glucose and fructose, that are joined together in refined sucrose. Sucrose burns fast and hot; long chain sugars burn slow and steady. It has been shown that while simple sugars cause or aggravate diabetes, long-chain polysaccharides heal the pancreas and counter diabetes.
The refractometer, unfortunately, can't tell tell us whether the sugars are simple or complex, and it's not likely that we are going to be willing to pay for the elaborate chemistry needed to sort them out, so what to do?
As has been mentioned before, one can get a plant tissue test for minerals; essentially the same thing as a soil test, but measuring the mineral elements that the plant has taken in.
One thing we know about complex micro-biological structures like polysaccharides and amino acids is that they require mineral catalysts in order to be formed or made. Phosphorus is necessary for all complex sugar formation. Zinc is known to be necessary for over three hundred enzymatic functions and likely plays a part in sugar complexity too. Calcium, Magnesium, Potassium, Boron, Iron, Manganese, and Copper are all essential for both plant and animal health. A crop that is deficient or unbalanced in any of them will not be truly healthy, nor will it make truly healthy food, despite cosmetic appearances.
At the present time most commercial and home garden agriculture is focused on high Nitrogen and Potassium fertilization. Mammals such as humans use around three times as much Phosphorus P as Potassium K, and over four times as much Calcium Ca as K. So why are we fertilizing with Potassium and Nitrogen?
Because they are common, easy, reasonably cheap, and give a good growth response, i.e. high yield. No real consideration is given to the nutritional quality of what is grown. How many tons per acre is the standard. We have already gone over all of that; just getting more detailed here.
Warning: Chemistry ahead!! (but stay with me please)
Back in the 1940s, Firman Bear and crew working at Rutgers U in New Jersey observed that alfalfa (lucerne) and other crops took in a fixed total sum of the cation (cat-eye-on) elements Ca++, Mg++, K+, and Na+. Those +plus signs indicate the charge on the different ions. Cations have a + positive charge, anions (an-eye-ons) have a - negative charge. Living things balance + and - in their body fluids to regulate pH, acidity or alkalinity. Plants and animals use Ca++, Mg++, K+ and Na+ to raise the pH and make the biology more Alkaline; they use the anion - elements NO3- (nitrate), SO4-- sulfate, and Cl- Chlorine, along with carbonic acid, to lower pH and make their fluids more Acid.
Note that Ca++ has two positives, K+ only has one. Cl- has one negative, SO4-- has two. To achieve a stable compound with SO4--'s two negatives would take one Ca++ or two K+'s.
The sum of the negative and positive charges equals the pH. A plant can take in 200 parts of Ca++ Calcium to balance its pH, if Calcium is freely available, or it can take in 400 parts of K+ Potassium, or 400 parts of Na+ Sodium to do the same job.
The question becomes, what do we want in our food? Once a plant has the minimal requirements of an element for its physiological processes, enough Ca, Mg, and K to function, it doesn't seem to care which "extra" cations it uses to balance its pH; it will use whatever is freely available. If that is Na Sodium, that is what it will use. If K Potassium is abundant while Mg Magnesium is scarce, the plant will pack on the K and be Mg deficient.
The same rule seems to apply to anion balance. If NO3 nitrate and Cl Chlorine are freely available while SO4 sulfate is rare, the plant will load up with what is easy to find and will be deficient in Sulfur. Sulfur is needed to synthesize at least two essential amino acids. Low Sulfur means a lack of complete protein.
Why does this matter? Because it seems that when plants take in lots of Potassium they are only able to make simple sugars, and when they take in lots of Nitrogen they only make simple amino acids and proteins.
Lacking the necessary catalysts such as Zinc and Phosphorus, lacking Calcium, Magnesium, or Sulfur, the plants can only produce simple and incomplete nutrients.
By focusing on the Nitrogen and Potassium levels of our soils we sacrifice nutritional completeness in order to achieve high yield. That sort of reasoning may work if one is growing fiber such as cotton; it does not work for growing good food.
Again the question, if high Brix is the sole goal, is it possible to grow high-Brix crops in depleted soils with chemical fertilizers like N and K? The super-sweet hybrid corn proves it can be done. If a high Brix reading is going to be where the money is, one can expect to see heads of broccoli and cabbage that Brix 12* yet have no more complete nutrients than the sweet corn.
That is why we need proof of mineral content via a laboratory plant tissue test. If that test shows a well balanced abundance of essential minerals, chances are the saccharides and the amino acids/proteins will be complete and varied, simply because the plants had everything they needed to grow to their fullest potential of flavor, aroma, and real food value.
If the crop is high in Potassium and/or Nitrogen, but low in Calcium, Magnesium, Phosphorus, and essential trace elements, we can safely assume that it is not going to be excellent food, regardless of its Brix reading.