carrotman-ga,
In general, the healthier the plant is overall, the higher the brix
(percent total sugars) levels it will have. As for what factors
specifically affect the brix content to the highest degree apart from
those knwon to affect the plant's general health, I’ll discuss that
below.
First of all, let’s get a formal definition of brix. From
[http://www.crossroads.ws/brixbook/BBook.htm#ORIGIN%20OF%20THE%20WORD%20BRIX
]:
“BRIX is a measure of the percent solids (TSS) in a given weight of
plant juice---nothing more---and nothing less. BRIX is often expressed
another way: BRIX equals the percentage of sucrose. However, if you
study the contents of this book, you will soon enough understand that
the "sucrose" can vary widely. For, indeed, the BRIX is actually a
summation of the pounds of sucrose, fructose, vitamins, minerals,
amino acids, proteins, hormones, and other solids in one hundred
pounds of any particular plant juice."
The same site offers a commentary
[http://www.crossroads.ws/brixbook/BBook.htm#ORIGIN%20OF%20THE%20WORD%20BRIX
]:
“BRIX varies directly with plant QUALITY. For instance, a poor, sour
tasting grape from worn out land can test 8 or less BRIX. On the other
hand, a full flavored, delicious grape, grown on rich, fertile soil
can test 24 or better BRIX.”
They go on to offer the following advice:
“I suggest that you remember that sugar is only one of the components
of brix. Also remember that many other substances can falsely indicate
"brix" readings (although those readings are valid in their own
right). Try rubbing alcohol, whiskey, vinegar, or wine. Interestingly,
cooking oil, molasses, syrup, and other thick liquids require a
refractometer calibrated to read 30-90 brix. Honey is checked with a
refractometer calibrated to measure the water within it instead of the
solids in the water.”
Okay, on to some specifically carrot-related brix information. Let’s
look at one study done by the University of Georgia, Department of
Food Science and Technology:
[http://www.ces.uga.edu/ES-pubs/RR653.html ].
Special Note: The webpage above is a long, single page, and they
didn’t use bookmarks to differentiate the various sections. So, to
find specifically what you want on the page, if you’re using MS
Internet Explorer, when the page is open, type [Ctrl]-F on your
keyboard. This will open a “Find” box which you can type phrases or
keywords into, and it will jump to that part of the page.
One of the objectives of this study was to “determine the relations
between oBrix, percent total sugars, moisture content and selected
sensory attributes of Georgia, California and Florida carrots.” So,
they aimed to determine the brix levels of each, and then try and
figure out what causes the differences in brix levels, if any.
From the study’s webpage [http://www.ces.uga.edu/ES-pubs/RR653.html ]:
“Carrots with the highest oBrix and percent total solids content were
used to select 5 cultivars. These carrots were stored for
approximately two weeks at 0 degrees C, 65% relative humidity and 2.2
degrees C, 80% relative humidity, respectively. Market samples of
carrots from Bakersfield, CA, and Apopka, FL, were purchased and
stored under identical conditions as the Georgia samples used in study
1, and samples from Bakersfield, CA, and Oviedo, FL, used in study 2.
The samples evaluated during the two studies are shown in Table 1.”
The following passage outlines how the brix measurements were taken.
(It’s important to note that just the measurement technique used can
affect the brix level noted—that’s why they’re so careful to list the
precise technique they used in measuring the brix levels from the
carrots), from [http://www.ces.uga.edu/ES-pubs/RR653.html ]:
“oBrix Measurements:
Three carrots of each replication were selected for measurements of
oBrix and percent total sugars. Approximately 2" was cut off from each
end and the middle portion was used for analysis. The samples were
blended into a puree using a retail juicer and filtered through
Whatman #1 filter paper to remove particulates. The filtrate was used
to obtain measurements of oBrix and percent total sugar. oBrix
measurements were obtained from 3-4 drops of the carrot juice placed
on the refractometer stage using a Pasteur pipette and directly
recorded.”
As far as the study’s results
[http://www.ces.uga.edu/ES-pubs/RR653.html ]:
“oBrix reading of the California carrots were highest and Florida
carrots lowest in study 1. Georgia carrots had intermediate oBrix
readings. 'XPH3973,' 'Choctaw' and 'Ireland' had the highest readings
among the Georgia carrots. In study 2, 'Dawn Dee' had the highest
oBrix reading followed by 'California 2' and 'Choctaw.' 'Cheyenne' and
'Florida 2' had lowest readings; however, 'Florida 2' was not
significantly different from 'Vitasweet,' 'Asgrow' and 'Florida 1.'”
And,
“oBrix reading of the California carrots were highest and Florida
carrots lowest in study 1. Georgia carrots had intermediate oBrix
readings. 'XPH3973,' 'Choctaw' and 'Ireland' had the highest readings
among the Georgia carrots. In study 2, 'Dawn Dee' had the highest
oBrix reading followed by 'California 2' and 'Choctaw.' 'Cheyenne' and
'Florida 2' had lowest readings; however, 'Florida 2' was not
significantly different from 'Vitasweet,' 'Asgrow' and 'Florida 1.'
'California 2' had the highest total sugar and Florida 1 and 2 had the
lowest total sugar in study 1. 'California 1' and all Georgia carrots
had intermediate total sugar readings. In study 2, 'California 2' had
the highest total sugar, followed by 'Choctaw' and 'Florida 2,' while
'Asgrow' had the lowest. However, there were no differences between
'Asgrow' and 'Florida 1,' which was similar to several other carrots.”
Note in particular the following point, indicating the even carrots
with migh measured brix levels may be perceived as less sweet due to
other factors [http://www.ces.uga.edu/ES-pubs/RR653.html ]:
“This indicates that while oBrix may be an indicator of the soluble
solids (includes sugars) in the sample, perceived sweetness and
overall acceptance may be rated lower when the carrots contain flavor
compounds such as those contributing harsh, carroty, bitter and
astringent flavors, which may affect the perception of sweetness.”
From the “Discussion” section
[http://www.ces.uga.edu/ES-pubs/RR653.html ]:
“In general, the acceptability of California carrots was highest,
followed by Georgia carrots then Florida carrots. In most instances,
some Georgia cultivars were not as acceptable as the California
carrots, but were more acceptable than Florida carrots. Some Georgia
cultivars were either more or less acceptable than the other Georgia
carrots.
Among the Georgia carrots, 'XPH 3973' and 'Vitasweet 711' were most
preferred. The 'XPH 3973' can compete with the California carrots on
overall acceptance. The flavor of 'Choctaw' carrots deleteriously
influenced its acceptance as demonstrated in both studies. 'Choctaw'
was found least sweet among the Georgia carrots. Although 'Choctaw'
had a high sugar content, its perceived sweetness does not reflect
this in study 1.”
The following data, from a Washington State University study,
[http://benton-franklin.wsu.edu/PDFDocs/carrot_juice95.pdf ], shows
early vs. late harvested carrots’ brix values. The late harvested
carrots have slightly higher brix values. The link is to a .pdf
document, so you’ll need Adobe Acrobat Reader to open it. Once it’s
open, click the binoculars icon on the toolbar to Find, and enter
keyword, “brix.”
Here’s an opinion from another source
[http://www.freshcut.com/carrotcountry/cc1998.htm ]:
“Desert Climate a Plus
In the pursuit of a high quality carrot, Mercer Ranch has another
factor in its favor: Southeastern Washington’s climate.
Both Meek and Beightol say you can’t beat the region’s hot summer days
and cool desert nights for growing carrots. The combination, says
Meek, creates high brix levels for a very nice-tasting carrot.”
The following research on factors responsible for high brix is being
done by Texas A&M University:
“Drip depth placement and irrigation rates using direct seeding and
containerized transplants are being evaluated on Texas A&M short-day
onion genotypes for growth, yield, bulb size, pungency, brix, and
quercetin content. We are also exploring subsurface drip irrigation
methods to increase water use efficiency and product quality of
special colored bell and poblano pepper; and the effects of ET rates
on triploid (3n) and dipolid (2n) watermelon fruit set, size, sugar
and lycopene content. Recently, water use efficiency, yield and
quality of muskmelons subjected to conventional furrow and subsurface
drip systems were determined on transplants versus direct seeding.
Across four seasons, sugar content was highest for transplants; the
average water applied for drip systems was 53% lower than applied with
conventional furrow systems, and water use efficiency was 2.3 times
greater for drip.”
Thus, they suppose that they specific type of irrigation may influence
the brix levels of the resulting crops.
The next link is to a Brigham Young University Food QA Lab page
titled, “Brix testing Techniqies”:
[http://bensonlab.byu.edu/testing_techniques/manual/brix.html ].
I include this link because how the brix is measured is extremely
important in determining the result. Handheld refractometers are
commonly used, but there is a wide variation of equipment used that
can make a difference in the brix readings obtained.
From jourrneytoforever.org
[http://journeytoforever.org/garden_organic.html ]:
“A plant's mineral and protein content, and protein quality, are
directly related to the sugar content in the sap.”
Another thing to consider is that the brix level of any fruit or
vegetable, including carrots, may diminish *after* packaging, en route
to the customer, due to microbial activity. The following paragraph
from an FAO.org webpage addresses this problem using dates as an
example, but it is a potential problem with carrots as well
[http://www.fao.org/DOCREP/004/AC300E/AC300e03.htm ]:
“After storage, dates are placed in a steam bath to stabilize the
fruit's moisture level and to pasteurize it. Before packaging, the
dates are sometimes coated with hot, pasteurized sugar syrup. This
coating, which has a high sugar content of 70 to 80° Brix, acts as a
barrier against contamination by micro-organisms (due to the low
absorption of water into the coating) and prevents the products from
sticking together. In this manner, despite a high water content (24%),
the development of micro-organisms in date packaging seems to be rare,
even among organic dates. However, to obtain these results, one must
ensure that good hygienic conditions are applied during processing.”
Google search strategy:
Keywords,
“carrot brix growth factors”:
://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=carrot+brix+growth+factors
,
“carrot brix nitrogen”
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=carrot+brix+nitrogen&btnG=Google+Search
,
“carrot brix”:
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=carrot+brix++&btnG=Google+Search
,
“daucus carota brix”:
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=daucus+carota+brix
,
“creating high brix carrots”
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=creating+high+brix+carrots&btnG=Google+Search
,
“carrot brix research”:
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=carrot+brix+research&btnG=Google+Search
Also, conduct all of the above searches substituting “daucus carota”
for “carrot” and vice-versa. Furthermore, clicking the “similar links”
gray colored link next to each search result main link will bring you
to more content similar to that of the last link. If you ever need
extremely detailed data on something very specific, it’s best to email
an authoritative source directly and request the information, such as
someone at FAO or one of the Universities (e.g. Texas A&M) that I
mentioned above.
Please do not hesitate to ask for Clarification to this Answer if
anything I’ve written here is not clear, or if I have omitted anything
that is important to you. I’ll be happy to go into more detail if it
is necessary for you.
Good luck in your agricultural endeavors!
Sincerely,
omniscientbeing-ga
Google Answers Researcher |
