1. Stephanie McCulloch, B.S. Environmental Science, Sustainable Agriculture concentration
Marissa Zuckerman, B.S. Environmental Science, Economics and Nutrition Promotion minors
Department of Environmental Science, Ithaca College, Ithaca NY
Ascorbic acid content in vegetative produce cultivated in aquaponic
and conventional systems: a comparative analysis
Background
Aquaponics systems are esteemed for low environmental impacts,
including resource efficiency and the removal of fertilizers and
pesticides during cultivation. Aquaponic system use is expanding
across the country to increase food accessibility to low-income “food
deserts.” In an effort to combat both environmental and nutritional
issues, the use of aquaponics is rapidly expanding. Many aquaponic
firms and laboratories claim that aquaponic produce is more nutritious
compared to conventional agriculture methods. However, little
research has been conducted to support these claims. Aquaponics
research in general is still developing as this field continues to
emerge.
Methods
The aquaponic system used for cultivation is a hydrotin grow-bed
system, located in the Center for Natural Sciences (CNS) at Ithaca
College. Aquaponic fish species utilized were blue tilapia
(Oreochromis aureus) and bluegills (Lepomis macrochirus). Samples
were cultivated to the allotted time for species maturity. Daily water
quality parameters were conducted, including temperature, pH,
ammonia, nitrite, and nitrate levels. Conventional samples were
purchased from an independent vendor within the same time frame
as aquaponic harvesting. Edible tissue samples for each produce
species were tested. Samples were analyzed via high-performance
liquid chromatography (HPLC) methods by an independent third-
party.
Purpose
The purpose of this study is to compare the nutritional quality of three
forms of vegetative produce cultivated in aquaponic systems in
comparison to conventional agriculture methods: plain-leaved kale
(Brassica oleracea), bell pepper (Capsicum annuum), and romaine
lettuce (Lactuca sativa L. var longifolia). Our study specifically focuses
on ascorbic acid content (Vitamin C), a common vitamin in the human
diet found in plant matter.
Bitler, Marianne, Haider, Steven. “An Economic View of Food Deserts in the United States.” Policy Retrospectives 30.1 (2010): 153–176. Print., Dong, Diansheng, and Biing-Hwan Lin. Fruit and Vegetable Consumption by Low Income Americans: Would a Price Reduction Make a Difference?. United States Department of Agriculture, 2009. Print. Economic Research Report., Dunn, Bruce, Shrestha, Arjina.
Hydroponics. Oklahoma State University, 2010. Print., Loneragan, J.F., Smith, F.W.. Plant Analysis: An Interpretation Manual. Vol. 2. Collingwood,VIC, Australia: CSIRO Publishing, 1997. Print., Morton, Lois, and Troy Blanchard. “Starved for Access: Life in Rural America’s Food Deserts.” Rural Sociological Society 1.4 (2007): 1–10. Print., Porter, Keith, Trautmann, Nancy. “Modern Agriculture: Its Effects on
the Environment.” Cornell University Natural Resources Cooperative Extension (2010): n. pag. Print. United States Food and Drug Administration. A Food Labeling Guide: Reference Values for Nutrition Labeling. (2008). Print.
Discussion
Results show that conventional kale and peppers had higher concentrations of ascorbic acid, while aquaponic lettuce had higher concentrations. While there were noticeable differences in concentrations, all samples fell
below average concentrations published by the U.S. Food and Drug Administration (FDA). Because results did not fall within the FDA’s average concentrations, the results of this study could be deemed inconclusive. Due
to small sample sizes and limited controls, future research efforts should focus on ensuring proper protocol and system controls. Overall, this study can be utilized to encourage continued development in aquaponics
research.
References
Table 1. Ascorbic acid content of three forms of vegetative produce cultivated
under aquaponic and conventional agriculture methods.
0.495
2.06
24
0.44
18.5
45.4
0
5
10
15
20
25
30
35
40
45
50
Lettuce Kale Pepper
Ascorbic Acid Content (mg/100g)
Produce Type
Aquaponic Sample
Conventional
Sample
Figure 1. Ascorbic acid content per 100g of lettuce, kale, and pepper analyzed.
Produce Type Cultivation Method Ascorbic Acid Content
(mg/100g sampled)
Lettuce Aquaponic 0.495
Lettuce Conventional <0.440
Kale Aquaponic 2.06
Kale Conventional 18.5
Pepper Aquaponic 24.0
Pepper Conventional 45.4
Results
Images 1 and 2 (above respectively). Romaine lettuce (Lactuca sativa L. var longifolia) and
bell pepper (Capsicum annuum) cultivated in the CNS Aquaponic system to maturity.