Question about Moringa drier

Plants Moringa
#1

Hello everybody, i hope all is well with you and your families, I have a question, do you think if I build a moringa drier with wood and zink and install lights, to dry the leaves, do you think those lights will take the vitamins from the leaves?

Do you have ideas of how to do a Moringa drier?

2 Likes
#2

Hey Lesly, your question must have gotten lost in the forum. Were you able to find an answer to your question?

#3

William, thanks so much for bringing this to our attention!

Hi Lesly,

We have built and utilized passive driers for moringa leaf drying in the past at ECHO’s campus in Florida, but we only were able to utilize them well when humidity was low. With ECHO East Africa, @James_Dontje1 has worked on direct and indirect solar driers and would be a great person to advise you on this specific project. Please see his article here: Direct Solar Dryers | ECHOcommunity.org and his website detailing his design modifications (based on one from Appalachian State University; diagram below).
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@Elliott_Toevs do we have plans for that very large passive dryer that used to be beside the moringa plot?

As far as loading rates go, I’ve found that passive drying works best with a thin layer (2-3 cm max) of moringa leaves; otherwise, you run the risk of them molding in the drier. Experimenting with what works locally may take some time to figure out! It took me a bit of time to figure out how best to dry them in the rainy, hot season, even with a forced-air drier.

I was also recently reminded of a hybrid (solar power fan) drier that our friends at Trees that Feed have designs openly available on: Hybrid Solar Dryer - Trees That Feed Foundation

As far as your question about if links will alter vitamin content of moringa leaves, I think it would depend on your light source and perhaps how long the light was on. If you share more about this, I could ask Dr. Witt (wrote ECHO Research Note 1 on moringa leaf nutritional values)

Stacy

#4

Hello, Lesly (and Stacy and all),

I will add a couple of comments ( a bit long) drawing on my experience:

  1. I have been able to dry things fairly well in high humidity conditions with the direct dryer. Most of my testing has been done within a literal stones throw of the Indian Ocean (I can see the water from my desk) just a few degrees south of the equator. Humidity we have in good supply! The direct dryer, which allows the sun to shine onto the food, has been key. I have also tried working with the Appalachian State dryer design and have had a hard time making it work well–spent a lot of time trying different chimney designs but have never been happy with the result. I think the physics work against it but describing that would take a longer message. In the references on the website, you will find some notes on “tunnel dyers” which have used this same direct dryer approach on a bit larger scale.

  2. For wet, heavy material like mangoes, I have found it best to get the slices into the dryer early in the day and have a long drying session that gets a dry surface “skin” on the fruit before going through the first night. That said, leaves and dryer foods have been easier in this climate. We have had a lot of rain for the past 6 weeks, and when it is raining it is often cloudy or partly cloudy. My spouse has dried both coconut chips and some curry leaves during this time. Both turned out well and passed the “humidity level in sealed container” test I use for research testing. She didn’t dry a lot at once, but I am pretty sure based on the experience we could have fully loaded the dryers with a layer 1-2 cm deep and gotten the job done.

  3. Your question about nutrient (esp vitamin) loss due to the light source is a valid one given that the food is exposed to the sun with these direct dryers. Yes, there is some loss. How much may depend on the kind of glazing as some glazings have UV screening material added to them which could protect the food. I assume that all food drying causes some nutrient loss, but that the trade off is between some loss versustotal loss due to the food being unavailable when not in season or due to spoilage. Here are some references (and notes) on this topic (although not specific to moringa) from a presentation on the direct solar dryer that is on the website Stacy refers to:
    :

Polyethylene and polycarbonate covers preserved more bioactive compounds usually damaged by UV
(Rodríguez-Ramírez, J.; L. L Méndez-Lagunas;A. López-Ortiz; S. Muñiz-Becerá; and K. Nair. “Solar drying of strawberry using polycarbonate with UV protection and polyethylene covers: Influence on anthocyanin and total phenolic content.” Solar Energy. Volume 221, June 2021, Pages 120-130)
Sensory attributes of dried mangoes and pineapples were acceptable with several solar drying methods, but were higher with more protection from direct sun and UV. Using UV protective plastic.
(Mohammed, S; M. Edna; and K Siraj. “The effect of traditional and improved solar drying methods on the sensory quality and nutritional composition of fruits: A case of mangoes and pineapples.” Heliyon. Volume 6, Issue 6, June 2020, e04163)
Some manufacturers list resistance to UV degradation and UV screening in specifications – but specific, reliable information is hard to get.

  1. Another relevant thing to note (also discussed on the website) is blanching. Generally blanching (putting the food into boiling water for a short time) has been done with vegetable storage methods to deactivate enzymes and thus result in better storage. In my explorations with drying leafy green vegetables, I have also found that blanching speeds drying time–even though the blanched leaves go into the dryer wetter than the unblanched leaves. I think the blanching may be breaking cell walls in a way that allows water to escape. Not sure how this will apply to moringa as the leaves are so small to start with. And blanching may cause more losses (and be harder to do) because of small leaf size. Stems are another issue–if stems are included in a bath of leaves, even if chopped, they dry more slowly. The leaves may be so dry they crumble, but there will be enough moisture remaining in the stems to allow mold to grow in a batch of dried leaves when they are sealed for storage. In my limited experience, moringa leaves are often stripped off the stems for preparation (and the stems are very thin), so maybe this won’t be an issue for moringa.

Hope this helps and feel free to reach out with comments and questions.

James