Wednesday, March 11, 2015

Search Challenge (3/11/15): Is the fruit getting sweeter?



It seems unlikely, but who knows? Maybe it's true.  

Today's Challenge comes to us from Regular Reader Miguel Viterbo.  Last week he wrote with an interesting question.  With his permission, I'm just going to quote his question as he sent it to me because it's a great example of the kinds of questions that we want to be able to answer.  (In fact, his writeup is much better than most.  Research questions are often vague and missing background and context--not here. This is an excellent Challenge statement.)  

My friends, family, and myself, have been noticing that in the most recent years (latest two to four years), fruits in Lisbon, Portugal are much sweeter than they were, especially in supermarkets and big superstores, where fruit was always worse than the one we could buy at local stores. 
Oranges and citrus fruits have been particularly noticeable in their increased sweetness.
We have no idea if this is a global trend, or if it's just true in Portugal.
At first, we tended to assume that supermarkets just got better at dealing with producers and acquired better stuff. In fact, most people I know didn't buy their fruit in supermarkets, so it's reasonable to expect that they had to fix that problem.
In the past months, though, we've heard rumors that farmers nowadays use sugar (or some kind of sweetener) added to the irrigation. Yesterday, the fruit shop owner in my neighborhood (whom I assume to be knowledgeable, because she has been picking her suppliers for 20+ years, and at a time was married to a producer herself, if I remember it right) told me that this was common knowledge (she said, "some time ago those sweeteners were added to the fertilizers, now they're within the irrigation itself").
(1) Is this true? Does this actually work to make fruit sweeter? 
(2) Should I be concerned?  Sugar is already hiding in so many everyday "non-sugar" foods (way more in the US than in Portugal, granted) that I don't want to take any more added sugar.  If it's really more sugar, how much more is it?  

I haven't spent any time trying to research this Challenge.  I didn't want to get a head start on this.  I want to check this out this along with all of you loyal Search Researchers.  

I have no idea if this is true, or if we're going to be chasing down an urban legend.  

That's why this is an especially interesting question:  We don't know how it's going to turn out!  

Let's begin on Miguel's Challenge.  What can you find out about this?  Is it true that farmer's are now adding sweeteners to their irrigation water?  

Unleash the hounds of Search Research!  Go!  

Let us know what you find out AND tell us how you did it. 

Search on.  



- Muito obrigado to Miguel Viterbo for this excellent Challenge.  

30 comments:

  1. It is truly excellent and interesting Challenge. A long time ago, someone told me to add to my fruit tress a bottle of soda. That this will make it sweeter and yes it works! However, I believe price will make it impossible. At least, in many countries.

    I will SearchReSearch this in more detail. A quick search[ fruit getting sweeter] Susan Brown, an apple specialist with the Cornell University Agricultural Research Station, denies that the fruit she is working on has more sugar, but acknowledges that “high-quality” fruit is defined, in large part, by a high level of “perceived sweetness.” (Which she achieves by creating a balance of sugar and acids, which otherwise tend to mask sweetness.) And the article also says: "The Times of London article claims that food scientists are breeding fruits and vegetables to be sweeter, so even our baseline understanding of what’s “naturally” sweet is changing. Is that true?

    You know, it’s cool because it has the sniff of conspiracy to it, it’s like “Ooh I think I found something!” but the stuff is so mixed it’s hard to be really sure. I know data that says yes and data that says no."

    I think it is a good way to start.

    ReplyDelete
    Replies
    1. Until now:

      Good day, Dr. Russell, fellow SearchResearchers

      Searched:


      [fruit irrigation increase sweetness]
      [cornell fruit lab]
      [fruit production water mixes]
      [increasing sugar | sweetness content fruit production]
      [techniques increase sugar in fruits]

      Increase Sugar in tomatoes.

      Lots of fun, new information and sites but not actual answer.

      I will search trying "sugar concentration"

      Delete
    2. [increase sugar concentration oranges]

      Orange Juice and the sugar level, which is measured in degrees Brix (percentages by weight of sugar in a solution)

      [Fruit growing more brix]
      [increase brix fruit production] Production and environment affect production, as Remmij mentions.

      [agricultural technologies increase brix fruits]
      controlling water changes sugar level
      California Safe Soil, LLC – Food Waste to Fertilizer

      Delete
  2. Query oranges production irrigation to increase sugar content

    http://www.bioatlantis.com/croptrials/trial_citrus_using_bioatlantis_seaweed_extract.htm

    Trials indicate that sugar content with bio extract during irrigation is showing positive results. Next step is to follow through from trials to actual practice.

    ReplyDelete
    Replies
    1. Measurement of sugar content would help manage sugar intake. Here's one solution

      https://vimeo.com/120216569

      But this may not fit your needs so

      http://www.plain2growsystems.com/why-you-should-use-a-degrees-brix-refractometer-to-check-plant-sugar-aka-nutrients-its-easy-and-cheap

      http://en.wikipedia.org/wiki/Brix

      Delete
    2. Query "sugar content increased" Newhall

      Link to papers referring to the Newhall & Cara Cara & references to Lane Late Oranges. Paper is [Effect of Different Fertilizer Treatments on the Sugar Accumulation in Newhall and Cara Cara Navel Orange Author: LiMing]

      http://www.dissertationtopic.net/doc/1793039 You can download the dissertation for details.

      Delete
  3. given the time frame Luís gave it may be a weather related issue - such is the nature of agriculture - in 2012 there was
    a heat wave during the bloom season of the Algarve oranges that resulted in a 70% decrease in production…
    may have resulted in other domestic varieties entering the market; e.g., Dom João Valencia, or Carvalhal or increased
    presence of Brazilian product - fruit or juice btw, Brazil (Portugal's old colony) leads the worlds sugar production.
    Algarve
    thanks to the Portugese for the orange… at least in the west
    looks inviting
    it would be helpful to have Luís identify the variety or varieties he is consuming - info should be available from the vendors or as part of the marketing in the supermarkets.
    peeling back the info
    tangerines
    examples of variation & Epsom salt reference
    Epsom salts (MgSO4), also called magnesium sulfate
    given the multitude of factors involved in agriculture, it is difficult to point at any single source as producing a widespread outcome
    re sugar intake - know your metabolism and moderation n all things is a wise general approach…
    and purchasing one of T.Cook's new $10k+ baubles to monitor your sugar levels might be good…? less money to buy sweets…
    rose gold & diamonds… and pearls - apple sweetness
    P&TNPG - "T to the I to the P&L spreadsheet"

    ReplyDelete
  4. My search strategy was based on two queries: and . The sweetness of an orange is determined by the nutrients used in fertilization. Nitrogen increases soluble solids (sugars) as well as slightly increasing the acidity of the fruit. However the key element in making sugars in fruits is chlorophyll. "Magnesium is the center of the chlorophyll molecule so plenty of magnesium means plenty of chlorophyll." Magnesium also increases the sugar in the sugar/acid ratio. So it seems that farmers may have altered their fertilizer components ratios in favor of magnesium and to a lesser extent nitrogen. From a Sept. 26, 2014 posting in Agro-Culture Liquid Fertilizers, The nutrients that matter to citrus production; www.agroliquid.com/the-nutrients-that-matter-to-citrus-production. In addition the Wall Street Journal Markets Main Online article of 6/19/2013 describes new rules being followed in California regulating the sweetness of oranges states that instead of using a specific sugar/acid ratio, harvest is now determined by the total sugar content. Fruit is ripening longer on the trees, creating both sweeter fruit and greater demand. From www.wsj.com, "In orange trade, success never tasted so sweet." So both the USA and Portugal are benefiting from chemistry and patience.

    ReplyDelete
  5. My search strategy was based on two queries: and . The sweetness of an orange is determined by the nutrients used in fertilization. Nitrogen increases soluble solids (sugars) as well as slightly increasing the acidity of the fruit. However the key element in making sugars in fruits is chlorophyll. "Magnesium is the center of the chlorophyll molecule so plenty of magnesium means plenty of chlorophyll." Magnesium also increases the sugar in the sugar/acid ratio. So it seems that farmers may have altered their fertilizer components ratios in favor of magnesium and to a lesser extent nitrogen. From a Sept. 26, 2014 posting in Agro-Culture Liquid Fertilizers, The nutrients that matter to citrus production; www.agroliquid.com/the-nutrients-that-matter-to-citrus-production. In addition the Wall Street Journal Markets Main Online article of 6/19/2013 describes new rules being followed in California regulating the sweetness of oranges states that instead of using a specific sugar/acid ratio, harvest is now determined by the total sugar content. Fruit is ripening longer on the trees, creating both sweeter fruit and greater demand. From www.wsj.com, "In orange trade, success never tasted so sweet." So both the USA and Portugal are benefiting from chemistry and patience.

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  6. Thanks, Dan, for having posted my questions. (And thanks for improving my English.)

    Sorry for not having been of help but I haven't had any time left today.

    Fruits I (and my friends) believe to have become better and better in the past 4 years or so:
    Orange. Definitely. I don't know the varieties but I will try to check tonight in the two main supermarket chains: Continente and Pingo Doce.
    Encore Mandarin. This was a new variety some 10 years ago and wow, how sweet they were! Some years later, encores became very uninteresting just like most supermarket fruits, even bitter some times, not much different from other mandarins. Then, this year they're back to being sweet!
    Watermelon. It could be excellent until the 1980s (although you had to choose it). Supermarkets "destroyed" it. I'd say it may be back to being sweet in the past two years. Not so sure about this one though.
    Tomato. In Portuguese we wouldn't call this a fruit, although technically it is as fruit as grapes or bananas. One variety that, a dozen years ago, wasn't sold in Portugal although it was common in Spain was "tomate em cacho" meaning nothing more precise than "tomato in a cluster / truss". Its taste was way fuller and sweeter than the usual tomato found everywhere (which was good until the 1970s). On that linked page for "tomate em cacho", they say that cherry tomato is a smaller type of the same variety but I doubt it. Cherry tomato has been steadily good until a few years ago, and it remained uninteresting since. Another variety came to Portugal more recently, and it has been of variable taste and sweetness: mini plum tomato. In sum, in the tomato case, the sweetness seems to be related to years and varieties, not to improved production of any kind.
    Others. Now that I think of it, almost everything but oranges seem to be sweeter just because they are in fact new varieties. Jonagold or Fuji apples, for example, only recently (past 10 years?) entered the Portuguese fruit market. McIntosh and Pink Lady are even more recent.

    Trivia: I haven't rechecked now but I remember having read that most citrus fruits are hybrids, including the common orange!

    ReplyDelete
  7. At Continente supermarket now. Orange variety sold now: Newhall. Before this they were selling Lane Late. According to the two helpful clerks in the fruit section, they've been really good, Newhall is better and they're precisely at their sweeteness peak now (meaning this time of the year). From now on they will become worse. As to Encores, they agree on my view (excellent a few years ago, then bland, now good again). I may have lead them to agree though. All citrus mentioned have been of Portuguese origin (meaning produced in Portugal).

    ReplyDelete
    Replies
    1. from UC Riverside:
      Newhall
      Lane Late
      Encore mandarin
      USDA
      a bit of orange history: what do you call a cocktail made with vodka and apple juice?

      Delete
    2. the “Anita Bryant” cocktail - vodka mixed with apple juice.
      Uma
      70's
      Ain't No Sunshine
      season to season

      Delete
  8. HI Everyone:
    Luis thank you for the questions. Anne and I did a quick search for sweeteners irrigation fruit trees and the only result that seemed to related was someone's blog post that was more of a rant on farmers using aspartame in irrigation water. So we added aspertame to the search and saw the same result but also got a link to the the MADSCI Network's botany question and answer page - http://www.madsci.org/posts/archives/2001-11/1004909937.Bt.r.html -Someone had posed a similar question and it was answered by Dr. David Hershey who said:
    "I doubt that there has been much research on the effects of aspartame on plants
    because it is a product intended for human consumption. You might want to
    contact the manufacturer, NutraSweet, and ask if they have done plant research
    with aspartame.
    At the levels aspartame is used in beverages, such as soda, it probably would
    have no harmful effect on plants. Aspartame is 180 to 200 times sweeter than
    sugar so very little is used in beverages. However, plants watered with sugared
    sodas will be harmed because the high concentration of sugar in the soda
    decreases the water potential and makes the water less available to the plant.
    The plants will suffer from lack of water. Also, plants roots, stems and leaves
    are not designed to absorb large organic molecules, such as sugars. Therefore,
    it would be difficult to get the aspartame into the plant.
    If very high concentrations of aspartame were dissolved in the irrigation water
    for plants, it would also cause a harmful decrease in the water potential.
    The first webpage in the references describes the chemical structure of
    aspartame and discussses how the human body breaks it down."
    Not knowing who Dr. David Hershey is we next did some research on him and found two sites with bios for him - http://www.actionbioscience.org/education/hershey.html - and - http://www.angelfire.com/ab6/hershey/bio.htm - which gave us enough confidence that the guy knew something about botany. We next tried searching in some of our science databases to see if there was anything and found no other results; we thought it couldn't be a wide-spread practice if we weren't finding any information.

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  9. Part 2 of our post:
    At this point we decided to reach out to social media, I have a good friend from high school who has his Ph.D in horticultural science and was until his recent retirement the director of the Longwood Graduate Program in Public Horticulture at the Univ. of Delaware. He received his B.A. in Biology from Rutgers College of Rutgers University and went on to earn an M.S. and Ph.D. from the University of Minnesota, both in Horticultural Science. So in my post I tagged him but hoped other friends would weigh in and that is indeed what they did. The early responses all seemed to not believe the claim of the sweetened irrigation water but several people offered to reach out to their farmer friends. Bob responded by saying root systems take up water and minerals but my guess (I;m not a plant physiologist) is that sugars would not transport to the fruit." he later added in - the sugar would be used by the soil borne bacteria and fungus before having any chance of being absorbed by the roots. And also, which sugar would you use in your irrigation water? Sweetness in fruits may not be sucrose alone, rather a complex of many sugars (carbohydrates). Another friend reached out to a chemist friend who also said the plants wouldn't absorb the sugars.

    So what has made the fruit sweeter? I have to admit I don't think fruit has gotten sweeter but I could see that this would be something that fruit growers would want seeing the American love of sugar. I thought that fruit plants had been hybridized to create a sweeter fruit. Bob Lyons confirmed that there has been much work in this field with fruits being pollinated for certain characteristics. Then another friend, who runs a llama farm in Washington followed that trail further and used a google search with criteria as "sugar content in apple varieties site:.edu" which led to this result - http://extension.psu.edu/plants/tree-fruit/commercial-tree-fruit-production/harvest/determining-apple-fruit-maturity - which says that the sugar content of the fruit is determined by when it is picked and how long it is stored. No where in this article does it mention that the addition of sugar to the irrigation system makes the fruit sweeter. If this is such a common practice one would think a large extension service such at the one from the Penn State College of Agricultural Sciences would have at least mentioned this method.
    Anne and I will try a few more sources - we used Google Scholar but not books so will give that a go but pretty sure this is an urban myth. If I hear from anyone else I'll share those responses. For now I think Anne and I are convinced that Aspartame or any other sweetener has not been ingested by our fruit!

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  10. With very little time to research myself, I decided to ask on Facebook, only to find out that, out of my more than a thousand connections, not a single one has any knowledge about fruit and crops. I must find new friends. A friend of a friend answered, however, although with just a partial answer. Potassium in fertilizers is, according to him, the culprit of added sugar content in oranges.

    I found some time to read the answers posted here so far and I can't find any link to any page spreading the rumour of sweeteners added to the irrigation.

    My main concern is not, in fact, how much more sugar I'm eating via sweet oranges but which kind of sugars (if the purported sweeteners are artificial, like Advantame or Sucralose or Aspartame; or of natural origin like Stevia; or anything else). Also, if this is not true, which potentially unhealthy chemicals, if any, are responsible for the perceived added sweetness. Sorry for not having been clear enough in my question.

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  11. Luis I was also wondering if some other factor was influencing the added sweetness such as different fertilizers. But it may actually just be that farmers are creating varieties of fruits that are sweeter. I also decided to try another search in Google Scholar and this time used the search query "sweeter fruits irrigation water" which led me to this article http://onlinelibrary.wiley.com/enhanced/doi/10.1002/jsfa.1968 The abstract of the article entitled Leaf:fruit ratio and irrigation supply affect seasonal changes in minerals, organic acids and sugars of mango fruit seems to indicate that the research showed that the more leaves on the fruit the sweeter it is. Using that same query led us to another article http://www.sciencedirect.com/science/article/pii/S0308814610003377 that seems to indicate that in cvs. (which I had to look up and found out it means cultivated varieties) Elsanta, Sonata and Symphony types of strawberries become sweeter by limiting the amount of irrigation at certain key times.
    So bottom line I think this addtional sweetness is the result of agricultural science using different watering/irrigation techniques (but not actually adding in sweeter to the irrigation water) and hybridization.

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    Replies
    1. Debbie and Anne, I hadn't read your very resourceful answers when I wrote my last one. Well done!

      (I still find I would want a clearer answer but it may be very difficult to find it, especially if it implies proving a negative, which is impossible, says I, or at least very hard.)

      I can't wait to read Dr Russell's answer. And to go back the fruit store owner and ask her for details of what she claims to know.

      Delete
  12. I think the answer is BioAtlantis Alga 95®. The treated fruits have a higher sugar content and higher yields.

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  13. My friends on FB on now interested in joining in Search Research! This was a really fun challenge! Loved reading everyone's answers and Luis thanks again for posing the question and for offering the comment!

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  14. I think it would be very difficult for a home consumer to measure objectively the amounts and types of sugars and acids. So this may be a perception problem rather than empirical.

    That said Joko appears to have found a product that claims to make fruits sweeter; http://www.bioatlantis.com/croptrials/trial_citrus_using_bioatlantis_seaweed_extract.htm

    Soil sweetener is typically potash used to make soil less acidic.

    Sugar would possibly upset the microflora in the soil. Would this matter?

    Have searched thru my Uni's 10,000 learned journals collection with nothing appropriate turning up.

    Nice day to be in Vancouver.

    Cheers

    jon TU

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  15. Thanks to Debbie G. for her thorough research and comments. I, too, could find no reputable source for adding sugar when irrigating. A few thought that the sweetener would not be taken up into the plant and that it might attract extra bugs/unwanted pests. The only sites touting sweeteners, sugar and/or pineapple juice were those trying to sell their products. As an extra point there were a few sites that declare that adding molasses to marijuana improved their product. Who knew?

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  16. … is "molasses" some sort of code for "Labradorian"? (from 1978…or 1878 or some other space-time continuum)
    wonder if Dan is crunching the big data on this one or went straight from Vancouver to Austin…? or was crossing the border from WA an issue…?
    at any rate, the resolution solution is still MIA — so many questions, so little data.
    bandana Dan… from the 70s?
    "Molasses is good in coffee."

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  17. As a corollary to this search, if sweetened irrigation water makes for sweeter fruits, does adding heat (as in spices) to the water make peppers hotter? Turns out that a very hot pepper has been developed by cross breeding different types of peppers. Came across this story on a site we use in our school called Newsela, Eating a Carolina Reaper chili won't kill you — it'll just feel like it, https://newsela.com/articles/hottest-chili/id/6221/ The article originally appeared in the LA Times. Turns out this variety of pepper was developed to be hotter by cultivating it. So it would make sense that if hotter peppers are developed by breeding them to be hotter and not by pouring hot sauce into the irrigation water than sweeter fruits are sweeter because they have been bred for this quality as well. Had so much fun with this challenge.
    Retired Librarian who knew about molasses?

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  18. An interesting angle, but I have no further evidence from my anecdotal research - it appears that adding sweeteners of any sort is not the practice here with Australian Fruit Growers either - but is interesting to note that changes in taste receptors and senses as we age can make it appear that, for example, tomatoes have lost their taste or apples are sweeter - it is the observer that is changing with age - not the fruit itself IMHO.

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    Replies
    1. That is a wonderful piece of trivia!

      It's clear to me that my ageing friends are losing their taste and therefore prefer sweeter and fattier food. Me too, although not to the extent of my friends in their eighties. I used to help my mom correct the salt just by smelling the food being cooked, or at least I claimed to be able to do it. Now, sometimes I'm not even sure if a particular meal is too salty or too garlicky for example.

      What surprises me is that claim that older taste buds and brains perceive apples as sweeter. Can you provide any source substantiating it?

      Delete
  19. Hi everyone, Sorry this is so late. Looks like it was a busy time for many of us. I wasn't able to thoroughly research this search because of time, but did begin a different way.

    I searched [ make orange crop sweeter ]. My thinking was if irrigation was the way to do this, it would be somewhere in the SERP. I didn't see any mention of irrigation. What did come up over and over again was the mention of how sweetness increases based on the age of the trees. I'm wondering if Luis is getting sweeter oranges because the groves his oranges come from is aging.

    Apologies again, I wasn't able to carry it through and actually find any solid proof that this is the case.

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  20. Hi everyone, maybe grafting trees could give sweeter fruits?

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  21. Maybe grafting is the key to sweeter fruits?

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