Iowa State University Report

Nutritional Value, Taste Considerations, and Antioxidant Content of Iowa Grown Aronia Berry Food and Beverage Products

Project Summary

Aronia berries, while not yet popular in the marketplace, have great potential to be considered a functional food due to its high values of antioxidant compounds. Some have even gone as far as to consider the Aronia berry a “Super Fruit.” While this term is not clearly defined, it is typically used as a marketing tool for fruits with known high levels of antioxidants. With all of the research being done recently on the health benefits of different berries, the question was raised “Could Aronia berries be considered in this category of functional foods?” Literature research suggests that Aronia berries contain many different antioxidant properties along with high levels of several different vitamins, but how do these values compare to other “Super Fruits” like blueberries? Also, do the antioxidant values in Iowa grown Aronia berries compare with those reported in previous research literature?

The purpose of the Aronia berry project is to analyze the Aronia berries for creditable nutrient content data.  This information could be used in feasibility studies, marketing plans, advertising campaigns, and basic food science knowledge.  The overall goal of this project is to compare Aronia berries composition and products to other berries and see if the Aronia berry has greater nutritional benefit. A second goal of the Aronia project is to use the berry in a variety of products common to fruits and evaluate the effect of processing on the phenolic compounds found in the Aronia berry

The motivation of this project was that a few Iowa producers of Aroniaberry producers were selling large quantities of bare rooted seedlings and cuttings to numerous small acreage owners, farmer’s market vendors, and small farming operations across Iowa.  Those new growers were buying 500 – 1000 plants and planting orchards of Aronia berry.  The northern Iowa growers came to the RC&D asking for advice on which food products produced with Aroniaberries were best suited to commercial production and marketing.  They wanted an option to selling their berries to the single largest producer in Iowa at wholesale prices.  They were interested in marketing the ‘super fruit’ themselves and processing it locally into various products.  These growers have three years to go until they harvest commercial quantities of their berries, during which time they will decide how to process and market the Aronia.

Project was not built on previously funded work.

 

Project Approach

A total of five different ‘batches’ of Viking Aronia berries were analyzed.  Four of the ‘batches’ were obtained by the North Iowa Aronia group, labeled and placed in the freezer for storage.  The 5th ‘batch’ was purchased from another farmer. All of the ‘batches’, were labeled and placed in the – 20 0 C freezer for storage.

One of the ‘batches’ contained smaller berries than the other ‘batches’.  The berries were graded, and the smaller, lesser grade berries, made up the sample. The smaller berry size could affect the composition of the sample, which was shown in the analysis that has been completed.

First, a pulper in Dr. Wilson’s lab was used to prepare the berries for the use of jam production. The product from the pulper still contained skin and a few seeds. The consistency was similar to thick Cream of Wheat.   This product could be used in jam making.

In the production of Aronia jam, recipes were obtained from an insert in the package of Sure Jell pectin used. Three jams were made and tested. Jam #1 and Jam #2 both contained 2 cups of berries, roughly chopped. The difference between two recipes was that Jam #1 used more sugar. Jam #2 was better perceived as it gave more of a balanced berry flavor.  A third jam was made utilizing a pulping blade on the Breville juicer to obtain berry pulps to potentially improve texture.

A juicer was used to juice the whole berries, however in order to obtain a clear juice, further filtration was applied. After vacuum filtration of the juice, analysis was run for Brix, pH, titratable acidity (malic acid content) as well as GC headspace and HPLC analysis.  In making juice for jelly, wine and syrup, 4 layers of cheesecloth overlapping in different directions removed most of the pulp in the juice.  The remaining juice was run through a coffee filter to obtain a clear juice.

The Aronia berry jellies were made from the clear juice of the berries. The first recipe tested was found in the Sure Jell pectin package, which suggested 2 cups of juice to 2 cups of sugar. This recipe made a weak gel. Juice sweating (weeping) out of the jelly was observed as well. For an ideal gel, the product should contain approximately 65% sugar (FDA; USDA AMS). In order to get this ideal sugar content, it was calculated that 2 cups of Aronia berry juice needed 2 5/8 cups of sugar. Jelly A was made with this recipe. Another jelly (Jelly B) was made with 3 cups of sugar to increase sweetness and make easier measurement.

A series of juice blends were taste tested containing varied amounts of Aronia in combination with commercial blueberry, pomegranate, black cherry, Concord grape, white grape, and apple juices.  While none of these juice blends were deemed palatable without large amounts of added sugar, these juice blends were considered when making products such as wines and syrups.

Syrup recipe development started with a pomegranate syrup recipe found on www.foodnetwork.com. After comparison with other fruit syrups, a basic recipe of 2 cups of juice with ½ cup of sugar and ½ tablespoon of corn syrup. During the early preliminary recipe testing, we found that it is difficult to achieve the desire consistency due to the vast differences in cooking temperature and time. Later attempts included monitoring time and temperature of the syrup while removing samples to cool so the true consistency could be determined. Syrups were made with all Aronia juice, as well as a combination of Aronia and grape and Aronia and black cherry juices. 50:50 blends of Aronia and grape were made as well as 50:50, 75:25, and 62:38 Aronia: black cherry blends. Sugar content was also adjusted to market products and consumer preference.

We made several wines with the simple recipe, juice, sugar and yeast. There were 4 wines with different juice blends. The Brix and alcohol contents of all the wines were monitored and recorded through the fermentation. Wines were put into the cooler when their alcohol contents were higher than 11% to stop the fermentation. Wine #1 was made with Aronia berry juice, white table sugar – sucrose (enough to bring the Brix to about 22 %) and 1.27 g of dry Champaign yeast (activated with 104 F water before adding to the mixture). Wine No.2 was made with a juice blend of 60% by volume of Aronia berry juice and 40% Concord grape juice, white sugar (about 148.5g enough to bring the Brix of the juice blend to 22% Brix) and dry Champaign yeast (activated in 104˚F water). Wine No.3 was made with a juice blend of 70% by volume of Aronia berry juice and 30% white grape juice, white table sugar (enough to bring the Brix of the juice blend to about 26%) and dry Champaign (activated in 104˚F). Wine No.4 was made with 60% Aronia berry juice by volume and 40% black cherry juice, white table sugar (enough to bring the Brix of juice blend to about 26%) and dry Champaign yeast (activated with 104˚F water). All the wines were very astringent and not palatable. They all had grassy odors. Wine No.2 (with Concord grape juice blend) and No.3 (with white grape juice blend) had the strongest grassy smell. In order to reduce the astringency, we chose to use gelatin as the fining agent. The gelatin (from LD Carlson Company) was obtained from the Heartland Homebrew supply in West Des Moines. The gelatin was added to wine No.2, No.3 and No.4 with a ratio of 1-teaspoon gelatin per 6 gallons of wine. After fining the wines for a week, they were racked.  Additional homemade wine obtained from the North Iowa Aronia Group was analyzed for pH, volatile acidity, total acidity, free SO2 and total SO2, and alcohol content.

Using High Performance Liquid Chromatography (HPLC), berry, juice, jam, jelly, syrup and wine were analyzed for citric acid, malic acid, tartic acid, ferulic acid, epicatichin, caffeic acid, catechin, procyanidin, idaein. The standard compounds that were analyzed were based on availability of the pure compound and its stated significance to the overall phenolic acid content of the berry. Samples for HPLC were prepared by centrifuging the samples for 15 minutes at 12K g. The supernatants were then dissolved with the mobile phase in a 1:3 ratio by volume. The mobile phase was a mixture of 95% 0.1 M KH2PO4 and 5% acetonitrile in a 1:4 ratio by volume. The mixture was then filtered using a 45 μm filter into HPLC vials.

The SafTest method of analysis was also run the jam, jelly, and syrup products to determine free fatty acid content, aldehyde content, and peroxide value.  However due to the low lipid content of the samples, results were too low to measure.

 

Goals and Outcomes Achieved

Both jams 1 and 2 had undesirable, gritty texture due to the skin and seeds of the berry.  Jam 3 had a less gritty texture than the previous ones, however, the Breville juicer only ground the skins and seeds to a finer particle size instead of eliminating the skins and seeds.  It was still too gritty to be consumed as a jam.  Also after being stored in the fridge for couple weeks, the jam gelled and became more of a mix between a jam and a jelly in texture.  In the future, using a commercial pulper to eliminate skins and seed may be a better option for making an Aronia jam. Of the jellies made, both Jelly A and Jelly B held a solid strong gel and had good flavor. However, it was determined that consumers might prefer Jelly B because it is sweeter.  Our favorite syrup was 1 ¼ cup Aronia juice, ¾ cup black cherry juice, 1 cup sugar and ½ Tbsp. corn syrup simmered for approx. 30 min after first boil.

An issue we encountered in making the juice blends was how to make Aronia berry the main component while concealing the astringency that makes it difficult to stand alone. The easiest way we found to reduce astringency was to add sugar.

In Aronia wine, the gelatin appeared to have a positive impact on reducing the astringency, but the flavor was not always improved by this addition. Continued aging of the wines as well as additional taste testing to increase the sugar content for a more palatable wine is recommended.

The headspace analysis of the pulp and juice using the Solid Phase Micro-extraction Gas Chromatography (SPME GC) did not return any substantial peaks, unless it was an older sample that was allowed to ferment, then Ethanol was present.  The same was found when the injection size was doubled to 2mL injection at 1mL/minute.

The Analysis of the five different ‘batches’ of Aronia berries is shown in Table 1. As this table shows, the composition of the berries differed greatly.  This can be most likely attributed to the different harvest time, unknown ages of the crop, storage conditions, as well as natural crop-to-crop variation (location and environment).

 

Table 1. Results of the analysis on Aronia berries

 

Batch 1 Batch 2 Batch 3 Batch 4 Batch 5
Brix 16.3 16.4 12.9 15.1 21.4
pH 3.5 3.53 3.91 3.49 3.33
Titratable acidity (g/L) 11.41 10.47 4.65 10.79 16.84
Sugar/acid ratio 14.3: 1 15.67: 1 26.46: 1 14.0: 1 12.72: 1
Tartaric acid (g/L) 3.7074 8.4681 15.7552 18.3699 5.4443
Malic Acid (g/L) 9.3696 10.062 3.5817 9.8224 11.8481
Lactic Acid (g/L) ——- ——– ——– ——— 7.0507
Acetic Acid (g/L) ——- ——– 0.8179 ——– ——–
Succinic Acid (g/L) 1.4026 ——– 2.7935 ——– 0.9552
Citric Acid (g/L) 2.44E-01 5.38E-01 0.6984 0.542 ——–

 

 These values were similar to values found in Chokeberry (Aronia melanocarpa)-A Review on the Characteristic Components and Potential Health Effects written by Sabine E. Kulling and Harshadai M. Rawel, which contains published data on the composition of Aronia berries.  The total amount of acids was found to be between 5 – 19 g/L.  The pH of fresh pressed juice was found to be 3.3 – 3.9 pH.  In fresh pressed juice L-Malic acid was found to have 9.0 g/L, Tartaric acid was not detected, Citric acid was 500 mg/L, Isocitric acid was 65 mg/L, Shikimic acid was 80 mg/L and Succinic acid was 1.5 g/L.  This report also contained information about vitamins, phytochemicals, and different phenolic constituents including procyanidins, anthocyanins, and flavonols.

Comparing the pH, Brix, titratable acidity and sugar acid ratio, as shown in Table 1, three of the batches, Batch 1, 2 and 4, are fairly similar and are treated as the same in the product development phase of the project.

The results from pH, volatile acidity, total acidity, free SO2 and total SO2, and alcohol content analysis are shown in Table 2.

 

Table 2. Homemade Aronia Wine from participating farmer

 

pH 3.42
Volatile Acidity 0.51 g/L
Total Acidity 9.37 g/L
Free SO2 6.40 ppm
Total SO2 101.66 ppm
Alcohol content 11.4%
Sugar Level < 0.2%

 

 The HPLC analysis of the berries and juices used for the production of the non blended Aronia products can be found in Table 3.

 

Table 3:  Summary of Phenolics in Aronia berry Products

Note:  Jelly A contained 0.56 g Aronia Juice/g Jelly, Jelly B contained 0.5088 g Aronia Juice/g Jelly, and Syrup 1 (pure Aronia syrup) contained 2.0438 g Aronia Juice/g Syrup.

As seen in Table 3, the Aronia berry contains the highest amount of phenolic compounds per berry.  When used as part of a product, the phenolic and acid compounds were the highest in the jelly and syrup products.  Because the jellies were produced first, it is possible that storage did not have as large of an effect on the total phenolics. In contrast, the juices made at a much later date, making them potentially susceptible to oxidation and temperature fluctuations during storage, were lower in phenolics. While the Aronia syrup has the highest concentration of phenolic compounds, the heating process used to concentrate the juice into the syrup resulted in the greatest percent (29%) loss of phenolics. These values are lower than researched literature. Some possible causes are the differences in extraction method for HPLC analysis, as well as large variation among berry crops from environmental factors. Also fresh Aronia berries were unavailable to us during the study and all the berries were shipped to us frozen. Finally, we did not know the age of the berry crop prior to handling of the berries for analysis. Storage conditions prior to arrival at ISU are also unknown, leading to potential causes of degradation of phenolics. Overall,. processing the Aronia berries into other food products overall maintained their phenolic (antioxidant) levels (71-90% retention).

Table 4 (See Page 11) shows the phenolic compounds of all Aronia products produced, including those blended with other juices. Syrups again showed the most phenolic and acid compounds due to the concentration of the juice to make the syrup.  Cherry juice and grape juice also are quite high in malic and tartaric acid. The addition of cherry juice to the Aronia berry juice increased the resulting blended juice’s phenolic content (Table 4). The wines showed a decrease in total phenolics and may continue to decrease as the wines are aged, as red grape wines, to increase their palatability.

Table 5 is a comparison of the Aronia berry and Aronia juice to berries commonly considered “Superfruits” due to high phenolic content. We can see from this table that with the same extraction method, the Aronia berry is comparable to cherry juice and much higher than blueberries. As noticed in table 5 that cherry was the only fruit that has higher phenolics content than Aronia berry. It is possible that because the cherry juice used in the experiment was reconstituted from commercial black cherry juice concentrate according to the direction of the package and there is no way to know if the dilution factor was dilute the concentrate to the original state of the juice or to the concentration that consumers like. Also studies have suggested that cherries do have a high level of antioxidant compounds and especially the black cherry (Prunus serotina) variety.

 

Table 5. Comparison to Aronia Berry and Juice to Common “Superfruits”

 

idaein procyanidin catechin caffeic acid epicatichin
Product mg/100g mg/100g mg/100g mg/100g mg/100g
Aronia berry 313.73 78.63 0.39 24.07 6.84
Blueberry 606.06 3.14 0.19 0.60 0.00
Juice run 1 0.00 0.00 14.10 0.65 4.06
Juice run 2 0.00 59.61 0.05 1.09 4.84
Concord grape juice 612.15 3.77 0.53 1.41 15.51
White grape juice 950.76 3.11 1.08 0.20 0.00
Cherry juice (from concentrate) 295.94 120.23 3.28 0.31 0.26
ferulic acid tartaric acid malic acid citric acid Total
Product mg/100g mg/100g mg/100g mg/100g mg/100g
Aronia berry 4.52 1411.76 1764.71 49.02 3655.02
Blueberry 0.00 838.38 1707.07 0.00 3155.64
Juice run 1 0.00 474.83 2127.26 332.38 2954.50
Juice run 2 0.00 1135.33 1429.80 238.42 2870.25
Concord grape juice 0.00 782.87 518.77 320.69 2255.94
White grape juice 0.00 848.90 660.25 0.00 2464.30
Cherry juice (from concentrate) 0.00 2950.15 1174.51 416.17 4961.35

 

 Beneficiaries

 

Beneficiaries are regional specialty crop producers in the Midwest who are growing aronia or are considering planting aronia as an orchard crop and who plan to market commercial products made from Aroniaberry.  It will assist in marketing decisions, help guide decision making and guide development of the industry.

Prairie Winds RC&D has distributed copies of the final report to the 90 + members of the Midwest Aronia Berry Growers Association and to 124 members of the North Central Iowa and Southern Minnesota regional marketing association named Local Food Producers Market Association.  The Minnesota Fruit and Vegetable Growers Association, and Iowa Fruit and Vegetable Growers, and the Regional Food Systems Working group at the Leopold Center for Sustainable Agriculture will also distribute the report to their members and display the report on their websites.  Prairie Winds RC&D will post the report on its website at prairiewindsrcd.com.  This meets our goal of a minimum distribution to 200 specialty crop producers having access to the report for their marketing decision making.

 

Lessoned Learned

It was determined that the total phenolic compounds found to be in Iowa grown Aronia berries are comparable to and in most cases higher than those found in other fruits commonly classified as “superfruits.”  Differences in the phenolic content of the berries received for testing purposes showed lower phenolic levels than literature values, but variation in analysis methods and conditions, sampling method and environmental conditions during growth and storage are the most likely contributing factors to the differences in these values. Comparison of the products to the frozen berries, the jellies showed the least amount of degradation of the phenolic compounds due to heating in processing. During the experiment, one of the biggest obstacles with the Aronia berry wines from a sensory point of view was the astringency of the wines. It is believed that tannin is the main contributor to the astringency. In this experiment, the wines were fined once with gelatin and barely had any aging. So they are considered very young wines. And in order to reduce the astringency, further fining and longer period of aging are believed to mellow out the astringency. However, as shown in this study, wines also showed degradation in phenolics, and it would be expected that these values would continue to decrease as the wine is aged. Overall, the products made from Aronia berries retained the majority of their phenoics/antioxidants and good color, which will allow these products to compete in the market place. Care must be made to formulate products that allow the astringency of the berries to be removed or hidden.

Also one of the most intriguing ‘side effects’ of Aronia berry during the experiment was the great coloring ability. Aronia berry has a very deep rich reddish purple color that is so concentrated in the berry that the berries and the juice appear to be almost black, which shows great potential to be an all nature coloring agent. And it retains the color very well under heat process, as all the jam, jelly and syrup products retained the deep rich color of Aronia berry after even an extended period of heating.

In future studies, a more quantitative study on the stability of the color versus pH, temperature and other various conditions are necessary to establish the potential of the utilization of Aronia berry as a colorant. Other future research possibilities include finding a way to determine whether and how much Aronia berry was used in the different products. Finding a benchmark compound or a specific ratio between certain compounds would allow us to determine the presence and amount of Aronia berry in a given product. Also, from an agricultural practical point of view, finding a way to tell the right time to harvest the berries would be essential to obtain the quality and processing potential of the berries. All of these studies would be important and valuable for the future use of Aronia Berries in foods and beverages.

Goals and expected outcomes were achieved.  They have of course led to many more questions about aronia berry product marketing as addressed above.  Overall jams,  jellies  and wines seems to be well sited products to market from aronia berries as they can be made from 100% berry product and do not require combining Aronia with other berry products to make pleasant tasting products if the recipes are adjusted to mask the astringency.  They represent the best products in terms of retaining their antioxidant value with during processing and therefore benefit from any health benefits associated oxidant content.

 

Contact Person

Teresa Nicholson, President

Prairie Winds Resource Conservation and Development Inc

641-923-3606 ext 5

wwb2@wctatel.net

 

Additional Information

References:

  • • Brown, Alton. 2006. Pomegranate Syrup or Molasses. FoodNetwork.com
  • • Kulling, Sabine E; Rawel, Harshadai M. 2008. Chokeberry (Aronia melanocarpa)-A Review on the Characteristic Components and Potential Health Effects. Planta Med 74:1625-1634
  • • Yashin. A. Ya. 2008. A Flow-Injection System with Amperometric Detection for Selective Determination of Antioxidants in Foodstuffs and Drinks. Russian Journal of General Chemistry 52(2): 130-135

 

See following page Table 4

 

***Funds for this project were provided by the USDA Specialty Crops Block Grant Program through the Iowa Department of Agriculture and Land Stewardship 
idaein procyanidin catechin caffeic acid epicatichin coumaric acid ferulic acid tartaric acid malic acid citric acid Total
Product mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g mg/100g
Aronia berry 313.73 78.63 0.39 24.07 6.84 1.35 4.52 1411.76 1764.71 49.02 3655.02
Juice run 1 0.00 0.00 14.10 0.65 4.06 1.23 0.00 474.83 2127.26 332.38 2954.50
Juice run 2 0.00 59.61 0.05 1.09 4.84 1.11 0.00 1135.33 1429.80 238.42 2870.25
Jelly a 344.31 15.79 0.13 0.46 0.76 0.49 1.46 883.23 583.83 7.49 1837.97
Jelly b (more sugar) 339.35 15.27 0.16 0.58 0.46 0.34 1.36 775.02 511.66 7.52 1651.73
syrup 1 331.65 100.79 0.06 1.00 0.00 2.18 5.57 1730.35 2876.71 230.71 5279.03
Aronia wine 491.54 22.06 1.10 0.28 3.07 0.39 4.55 454.95 811.00 989.02 2777.94
Aronia & Concord grape wine 431.02 52.16 2.62 0.17 3.46 0.63 4.78 965.56 1015.33 218.99 2694.71
Aronia & Cherry wine 463.50 22.88 0.87 0.81 2.70 0.40 3.86 515.00 703.18 178.27 1891.48
Aronia & White grape wine 470.54 29.01 0.96 0.45 0.00 0.34 10.07 438.64 697.84 139.57 1787.41
Aronia & Grape syrup 322.47 37.55 0.00 0.40 0.71 1.13 2.16 2121.10 1483.34 236.47 4205.33
Aronia & Cherry syrup 213.52 135.52 0.00 1.20 1.26 2.93 2.63 2412.81 4797.15 711.74 8278.77
Aronia cherry syrup more sugar added 208.93 69.74 0.12 0.64 0.82 1.04 0.00 1909.22 1066.28 381.84 3638.64

 

Appendix

Table 4


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