Nutritional Quality of Dry Vegetable Soups

Abstract

Dry soups with vegetables are often perceived as having low nutritional quality, but there are only limited data on the nutritional value of dry soups. Therefore, we measured the nutritional composition of dry vegetable powders used in dry soups and compared the results with published data on fresh and cooked vegetables. We also analyzed the nutritional composition of dry vegetable soups and compared these with published data on home-made and other soups. Dietary fiber, minerals, vitamins, and carotenoids in dry vegetables powders and soups were analyzed. Based on these data, a nutrient density score was calculated as measure of overall nutritional quality. Nutrient density scores for fresh and cooked vegetables, as well as home-made and other soups, were calculated based on the United Stated Department of Agriculture (USDA) and “Bundeslebensmittelschlüssel” (BLS) food composition data. The nutrient density scores of dry vegetable powders did not systematically differ from cooked vegetables. Nutrient contributions to European Food and Safety Authority (EFSA) dietary reference intakes per 250 mL serving of soup ranged from 11–45% for fiber; 3–23% for iron, magnesium, and zinc; 8–22% for potassium; 11–15% for vitamin A; 2–17% for B-vitamins; and 2–15% for vitamin K. The nutrient density scores of dry vegetable soups were in the same order of those of home-made and other soups. These data indicate that dry vegetable soups, like home-made soups, can deliver a significant part of recommended daily nutrient and vegetable intake.

Full text

nutrients
Article
Nutritional Quality of Dry Vegetable Soups
Leo van Buren 1, Christian H. Grün 1, Silke Basendowski 2, Martin Spraul 2, Rachel Newson 1
and Ans Eilander 1, *
1Unilever R&D Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands;
leo-van.buren@unilever.com (L.v.B.); christian.grun@unilever.com (C.H.G.); newson_rachel@lilly.com (R.N.)
2Unilever R&D Heilbronn, Knorrstrasse 1, D-74074 Heilbronn, Germany; silke.basendowski@gmx.de (S.B.);
martin.spraul@unilever.com (M.S.)
*Correspondence: ans.eilander@unilever.com; Tel.: +31-6-1138-5661
Received: 8 May 2019; Accepted: 2 June 2019; Published: 4 June 2019


Abstract:
Dry soups with vegetables are often perceived as having low nutritional quality, but there
are only limited data on the nutritional value of dry soups. Therefore, we measured the nutritional
composition of dry vegetable powders used in dry soups and compared the results with published data
on fresh and cooked vegetables. We also analyzed the nutritional composition of dry vegetable soups
and compared these with published data on home-made and other soups. Dietary fiber, minerals,
vitamins, and carotenoids in dry vegetables powders and soups were analyzed. Based on these data,
a nutrient density score was calculated as measure of overall nutritional quality. Nutrient density
scores for fresh and cooked vegetables, as well as home-made and other soups, were calculated based
on the United Stated Department of Agriculture (USDA) and “Bundeslebensmittelschlüssel” (BLS)
food composition data. The nutrient density scores of dry vegetable powders did not systematically
differ from cooked vegetables. Nutrient contributions to European Food and Safety Authority (EFSA)
dietary reference intakes per 250 mL serving of soup ranged from 11–45% for fiber; 3–23% for iron,
magnesium, and zinc; 8–22% for potassium; 11–15% for vitamin A; 2–17% for B-vitamins; and 2–15%
for vitamin K. The nutrient density scores of dry vegetable soups were in the same order of those of
home-made and other soups. These data indicate that dry vegetable soups, like home-made soups,
can deliver a significant part of recommended daily nutrient and vegetable intake.
Keywords: dry soups; dry vegetables; nutritional composition; nutritional density score
1. Introduction
Multiple studies have indicated that a higher intake of vegetables is associated with a reduction
of cardiovascular diseases (CVDs) and possibly with a reduction of obesity, type 2 diabetes,
chronic respiratory diseases, and some types of cancer [
1
–
6
]. The benefits of vegetables on the
prevention of non-communicable diseases (NCDs) may be explained by their relatively high content
of micronutrients, antioxidant compounds, polyphenols, and fibers, which may each counteract the
biochemical processes that cause CVDs and other NCDs [
7
,
8
]. According to the Global Dietary Database
1990–2010, vegetable (including legumes) intake ranged from 35–493 g/day, with a mean intake of
209 g/day. The authors concluded that the intake was, in most countries, lower than recommended to
prevent chronic diseases [9].
Health authorities such as the World Health Organization/Food and Agriculture Organization
(WHO/FAO) recommend a daily intake of
≥
400 g/day fruits and vegetables, which corresponds to
five or more servings of 80 g/day [
10
]. Many countries add to this recommendation that three out of
these five servings should come from vegetables (
≥
240 g/day). WHO/FAO does not include tubers
such as potatoes and cassava in their definition of vegetables [
11
]. However, unclarity exists as to
whether all vegetable sources (e.g., sauces, meals, and soups) can be regarded as a vegetable. In the
Nutrients 2019,11, 1270; doi:10.3390/nu11061270 www.mdpi.com/journal/nutrients

Nutrients 2019,11, 1270 2 of 11
UK, for example, processed vegetables in frozen, canned, and dried form, as well as vegetable juices,
are included to meet the recommendation [
12
]. At the same time, dried vegetable powders do not
qualify to count as a vegetable portion according to guidelines on calculating and communicating
fruit and vegetable portions in composite foods by the Institute of Grocery Distribution in the UK [
13
].
As a consequence, most definitions do not include vegetables in dried soups, although these products
may be a significant source. A general lack of adequate data on the nutritional composition of dried
vegetables and dried vegetable soups may underlie these decisions.
The drying or dehydration of vegetables is applied to preserve vegetables and their flavors
and nutrients. Drying methodologies include osmotic, convective, fluidized bed, ohmic, microwave,
vacuum, and freeze-drying techniques [
14
]. Before the actual drying phase, there is a pre-processing
step to remove foreign materials and to select, wash, occasionally peel, deseed, and reduce the size
of the vegetables. Techniques such as blanching, acid treatment, and the application of coatings are
regularly applied to preserve the quality of the vegetables [
14
]. Though the industrialized drying
process is optimized to maximally preserve food quality, both pre-processing and drying may degrade
certain nutrients, particularly heat-labile nutrients, such as flavonoids, carotenoids, and vitamins [
15
].
As chemical analyses of nutrients are expensive, there are limited published data on the nutritional
composition of dried vegetable soups. Data on these products in food composition tables (FCTs)
originate in most cases from a limited number of data sources that may be based on outdated analytical
methods. To judge whether the vegetables in these soups qualify as vegetables for recommended
intakes, there is a need for better data on the nutritional composition of dried vegetable soups.
The current study aimed to measure the nutritional composition of dry vegetable powders used
in dry soups and to compare these with published data of fresh and cooked vegetables. Its second aim
was to assess the nutritional composition of dry vegetable soups and to compare these with published
data of home-made and other soups. Based on these data, the fresh vegetable equivalents of dry
vegetable powders in dry soups will be determined.
Nutrients 2019, 11, x FOR PEER REVIEW 2 of 11
whether all vegetable sources (e.g., sauces, meals, and soups) can be regarded as a vegetable. In the
UK, for example, processed vegetables in frozen, canned, and dried form, as well as vegetable juices,
are included to meet the recommendation [12]. At the same time, dried vegetable powders do not
qualify to count as a vegetable portion according to guidelines on calculating and communicating
fruit and vegetable portions in composite foods by the Institute of Grocery Distribution in the UK
[13]. As a consequence, most definitions do not include vegetables in dried soups, although these
products may be a significant source. A general lack of adequate data on the nutritional composition
of dried vegetables and dried vegetable soups may underlie these decisions.
The drying or dehydration of vegetables is applied to preserve vegetables and their flavors and
nutrients. Drying methodologies include osmotic, convective, fluidized bed, ohmic, microwave,
vacuum, and freeze-drying techniques [14]. Before the actual drying phase, there is a pre-processing
step to remove foreign materials and to select, wash, occasionally peel, deseed, and reduce the size
of the vegetables. Techniques such as blanching, acid treatment, and the application of coatings are
regularly applied to preserve the quality of the vegetables [14]. Though the industrialized drying
process is optimized to maximally preserve food quality, both pre-processing and drying may
degrade certain nutrients, particularly heat-labile nutrients, such as flavonoids, carotenoids, and
vitamins [15]. As chemical analyses of nutrients are expensive, there are limited published data on
the nutritional composition of dried vegetable soups. Data on these products in food composition
tables (FCTs) originate in most cases from a limited number of data sources that may be based on
outdated analytical methods. To judge whether the vegetables in these soups qualify as vegetables
for recommended intakes, there is a need for better data on the nutritional composition of dried
vegetable soups.
The current study aimed to measure the nutritional composition of dry vegetable powders used
in dry soups and to compare these with published data of fresh and cooked vegetables. Its second
aim was to assess the nutritional composition of dry vegetable soups and to compare these with
published data of home-made and other soups. Based on these data, the fresh vegetable equivalents
of dry vegetable powders in dry soups will be determined.
2. Materials and Methods
2.1. Nutrient Content Analyses of Dry Vegetable Powders and Dry Vegetable Soups
We analyzed the nutrient content of dry vegetable soups and also analyzed the dry vegetable
powders that were used as main ingredients for the soups. Therefore, four commonly consumed
vegetable soup varieties commercially available on the European market, including dry tomato,
onion, pumpkin, and legumes/pulses (lentil and bean) soups, were selected for the nutrient analyses.
A fifth soup type comprising a mixture of vegetables was added to cover a wider range of variety in
vegetable ingredients such as celeriac, carrot, leek, beetroot, and broccoli. The trade names and
composition of all soups can be found in the supplemental data S1. For each type of soup, two
varieties were selected so that in total 10 dried soup products were analyzed.
Three packs of each soup product were obtained directly from the filling line in the different
Knorr factories in Europe. We also took three samples of 200 g of the dry vegetable powder that was
the main ingredient of each soup variety (covering 39–96% of the ingredients), including tomato,
onion, pumpkin, and lentil powder.
Terminology:
Dry soups: Packaged soup mixes of dry ingredients that need to be reconstituted with
hot water
Home-made soups: Soups that are prepared at home with fresh ingredients
Packaged soups: Wet or dry soups that are manufactured by the industry and
packaged in cartons, cans, or pouches.
2. Materials and Methods
2.1. Nutrient Content Analyses of Dry Vegetable Powders and Dry Vegetable Soups
We analyzed the nutrient content of dry vegetable soups and also analyzed the dry vegetable
powders that were used as main ingredients for the soups. Therefore, four commonly consumed
vegetable soup varieties commercially available on the European market, including dry tomato, onion,
pumpkin, and legumes/pulses (lentil and bean) soups, were selected for the nutrient analyses. A fifth
soup type comprising a mixture of vegetables was added to cover a wider range of variety in vegetable
ingredients such as celeriac, carrot, leek, beetroot, and broccoli. The trade names and composition of
all soups can be found in the Supplemental data S1. For each type of soup, two varieties were selected
so that in total 10 dried soup products were analyzed.
Three packs of each soup product were obtained directly from the filling line in the different Knorr
factories in Europe. We also took three samples of 200 g of the dry vegetable powder that was the
main ingredient of each soup variety (covering 39–96% of the ingredients), including tomato, onion,
pumpkin, and lentil powder.

Nutrients 2019,11, 1270 3 of 11
Samples were shipped at ambient temperature to the laboratory “Institut Kuhlmann GmbH
Analytik-Zentrum” (Ludwigshafen, Germany), where samples were homogenized and subsequently
analyzed in triplicate. Insoluble and soluble high and low molecular weight fiber were determined by
AOAC 2009.01 and expressed as total dietary fiber. Magnesium, iron, zinc, potassium, and sodium
were determined via microwave digestion followed by analysis by ICP-OES (ISO-16943).
β
-carotene,
lycopene, and lutein were determined by HPLC Diode-Array Detection (HPLC-DAD). Provitamin A
β
-carotene was converted to retinol activity equivalents using a factor 12. Thiamin (vitamin B1)
and riboflavin (vitamin B2) were determined by HPLC with fluorescence detection; niacin (vitamin
B3), pantothenic acid (vitamin B5) and pyridoxine and pyridoxal (vitamin B6) were determined by
HPLC-MRM-MS, and total folate was determined by measuring the turbidity of Lactobacillus casei
growth according to AOAC 2004.05. Total vitamin C was determined by extracting the samples
with meta-phosphoric acid solution followed by a homocysteine treatment and quantification by
HPLC-DAD. Phytomenadione (vitamin K1) was determined after fat reduction with lipase and
extraction with hexane, and it was quantified by HPLC with fluorescence detection.
Because the amount of dry soup to prepare a serving of 250 mL ranged from 16 g dried powder
for onion soup to 67 g for the dried lentil soup, the nutrient values of the dried soup powders were
expressed per serving size to allow a practical comparison between soup varieties.
The nutrient values of the dried powders and soups per serving were compared to the dietary
reference intake (DRI) values by the European Food Safety Authority [16].
2.2. Nutrient Density Score Calculation to Compare Nutritional Quality of Dry Vegetable Powders and Soups
with Published Data of Vegetables and Soups
A nutrient density score was calculated as measure of overall nutritional quality of each dried
vegetable powder and soup, based on a method by Drenowski et al. [
17
]. For each individual nutrient
in the vegetable powder or soup, a nutrient density score was calculated by dividing the nutrient
content per 100 g product by the European Food and Safety Authority (EFSA) dietary reference values,
which was then divided by the energy density and subsequently multiplied by 100. The overall
nutrient density score for each product was calculated as the sum of all individual nutrient density
scores of beneficial nutrients (i.e., total dietary fiber, magnesium, iron, zinc, potassium, vitamin A,
thiamin, riboflavin, niacin, pantothenic acid, pyridoxine, vitamin C, and vitamin K1) minus the sum
of the nutrient density scores of negative nutrients (i.e., sodium). The energy content of the dried
powders and soups was not analyzed and therefore derived from the food composition table values
for cooked vegetables (for powders) and nutritional information table on pack (for soups).
To allow for comparison of the nutrient density scores based on the analyzed data of the dry
vegetable powders with the respective fresh and cooked vegetables of the same variety (i.e., tomato,
onion, pumpkin, lentil, and mixed vegetables), the overall nutrient density scores of the latter were
calculated based on published data from the United Stated Department of Agriculture (USDA) National
Nutrient Database [
18
] and the German “Bundeslebensmittelschlüssel” (BLS) version 3.01 [
19
]. To allow
for a comparison of the five varieties of dry vegetable soups (i.e., tomato, onion, pumpkin, lentil,
and mixed vegetables) with respective home-made and other soups, overall nutrient density scores
were calculated for home-made and other soups with similar main vegetable ingredients. Data on
vegetables from mixed dishes, soup-based sauces, and stews were not included. Soup was classified as
home-made when this was included in the description of the product in the database. Types of soups
other than dry and home-made such as packaged soups (e.g., canned) and soups consumed out of
home were classified as other soups.
Some nutrients were not included in the overall nutrient density score of particular vegetable
powder and soup varieties because these were not analyzed or were below the detection level. This was
the case for vitamin C in all except tomato soups, vitamin K1 in pumpkin soups, and vitamin A in
onion, pulses, and legume soups.

Nutrients 2019,11, 1270 4 of 11
2.3. Calculation of Fresh Vegetable Equivalents in Dry Vegetable Soups for Comparison with
Vegetable Recommendation
To assess the vegetable content of the dry vegetable soups, we calculated fresh vegetable equivalents
by multiplying the quantity of each dry vegetable powder in the soup with a factor to account for
rehydration. This factor was obtained by dividing the weight of the dried vegetable powder (corrected
for remaining water content as provided by the ingredient suppliers) with the dry weight of the
fresh vegetable. Fresh vegetable equivalents of the dry soups were compared to the vegetable intake
recommendations of 240 g/day from the WHO/FAO [10].
3. Results
3.1. Nutrient Content of Dry Vegetable Powders
Table 1provides the analyzed nutrient content of the dry vegetable powders used as main
ingredient of the dry vegetable soups. Onion powder was more than three times higher in dietary
fiber (61.5 g/100 g) than tomato, pumpkin, and lentil powder (17.0–17.9 g/100 g). Lentil powder
contained two times more iron (7.8 mg/100 g) and zinc (3.8 mg/100 g) than the other vegetable powders
(3.3–4.8 and 1.3–1.7 mg/100 g, respectively). Tomato powder contained more niacin (11.9 mg/100 g) than
the other vegetable powders (1.0–4.0 mg/100 g), and it also contained significant amounts of provitamin
A from βcarotene (210 µg RAE/100 g), vitamin C (151 mg/100 g), and vitamin K1 (25.5 µg/100 g).
Table 1. Mean nutrient content of dry vegetable powders.
Nutrient Per 100 g Tomato Onion Pumpkin Lentil
Total dietary fiber (g) 17 ±0.2 162 ±2 18 ±0 18 ±0
Magnesium (mg) 166 ±2 112 ±1 128 ±2 104 ±1
Iron (mg) 4.8 ±0.2 4.1 ±0.4 3.3 ±0.1 7.8 ±0.1
Zinc (mg) 1.3 ±0.1 1.5 ±0.0 1.7 ±0.1 3.8 ±0.1
Potassium (mg) 4.0 ±0.0 0.9 ±0.0 2.5 ±0.0 1.0 ±0.0
Sodium (mg) 0.2 ±0.0 21 ±0 11 ±0 0.0 ±0.0
Vitamin A (µg RAE) 2210 ±11 NA 3138 ±1 NA
Lycopene (mg) 102 ±9 NA NA NA
Lutein (mg) 1.1 ±0.0 NA 4.3 ±0.1 NA
Thiamine (mg) 0.2 ±0.0 0.1 ±0.0 0.1 ±0.0 0.3 ±0.0
Riboflavin (mg) 0.5 ±0.0 0.1 ±0.0 0.4 ±0.0 0.2 ±0.0
Niacin (mg) 12 ±1 1.0 ±0.0 4.0 ±0.2 2.1 ±0.1
Pantothenic acid (mg) 0.6 ±0.0 0.6 ±0.1 1.5 ±0.0 0.9 ±0.0
Pyridoxine (mg) 0.6 ±0.1 0.5 ±0.0 0.7 ±0.0 0.3 ±0.0
Folic acid (µg) 268 ±41 152 ±18 277 ±23 109 ±11
Vitamin C (mg) 151 ±11 <LOQ 4<LOQ <LOQ
Vitamin K1 (µg) 26 ±1 NA NA NA
Nutrient density score 5315 142 335 394
1
Values are means
±
SD of two varieties of each dried vegetable type (e.g., the nutritional composition of tomato
powder was based on the mean of the values of two tomato powder varieties).
2
Vitamin A was calculated from
analyzed
β
-carotene values that were converted to retinol activity equivalents.
3
NA =not analyzed.
4
LOQ =limit
of quantification; for vitamin C this was set at 10 mg/100 g dry vegetables.
5
Based on total dietary fiber, magnesium,
iron, zinc, potassium, vitamin A, thiamin, riboflavin, niacin, pantothenic acid, pyridoxine, vitamin C, and vitamin
K1 as positive nutrients and sodium as a negative nutrient, with the exception that vitamin C and K1 were not
included in the score for onion, pumpkin, and lentil; vitamin A was not included for onion and lentil powders.
3.2. Comparison of Nutrient Density Scores of Dry Vegetable Powders with Fresh and Cooked Vegetables
Table 2shows the overall nutrient density scores of the analyzed dry vegetable powders next to
the nutrient scores of the respective fresh and cooked vegetables according to nutrient content in the
food composition databases. The overall nutrient density scores ranged from 142 for onion powder to
394 for lentil powder. For onion, pumpkin, and lentil, the overall nutrient density scores did not differ
between dry and cooked vegetables. The dry tomato powder (315) had a lower nutrient density score
than cooked (425) and fresh (473) tomatoes.

Nutrients 2019,11, 1270 5 of 11
Table 2.
Nutrient density scores for dry vegetable powders as compared to respective cooked and
fresh vegetables.
Mean and Ranges of Nutrient Density Scores 1,2
Dried
(Measured n=2)
Cooked
(BLS/USDA n=2)
Fresh
(BLS/USDA n=2)
Tomato 315 (309–321) 425 (319–531) 473 (408–537)
Onion 142 (130–154) 127 (57–197) 150 (77–223)
Pumpkin 335 (317–353) 320 (336–380) 361 (304–341)
Lentil 394 (365–424) 256 (142–317) NA 3
1
The ranges show the mean and lowest and highest nutrient density score for the two dry vegetable powders and
for the values in the BLS and USDA for either fresh and cooked vegetables (without fat).
2
Values are based on
total dietary fiber, magnesium, iron, zinc, potassium, vitamin A, thiamin, riboflavin, niacin, pyridoxine, vitamin C,
and vitamin K1 as positive nutrients and sodium as a negative nutrient, with the exception that vitamin C and
K1 were not included in the score for onion, pumpkin, and lentil; vitamin A was not included for onion and lentil
powders. 3NA, not applicable.
3.3. Nutrient Content of Dry Vegetable Soups
Table 3shows the nutritional composition of the dry vegetable soups per serving of 250 mL.
The lentil soup contained the most nutrients per serving, with contributions to the DRI per serving of
45% for fiber, 17–23% for minerals, 8–17% for B-vitamins, and 15% for vitamin K. For the other soups,
nutrient contributions to the DRI per serving were 11–21% for fiber, 3–6% for iron, magnesium and
zinc, 8–22% for potassium, 11–15% for vitamin A, 2–12% for B-vitamins, and 2–14% for vitamin K.
Vitamin C could only be detected in the tomato soup, where one serving contributed to 18% DRI.
Folic acid could not be detected in any of the soups.

Nutrients 2019,11, 1270 6 of 11
Table 3. Mean nutrient content and nutrient density scores of dry vegetable soups.
Nutrient Content of Dry Vegetable Soups per 250 mL Serving
Tomato Onion Pumpkin Pulses/Legumes Mixed Vegetables
Mean ±SD 1% DRI 2Mean ±SD % DRI Mean ±SD % DRI Mean ±SD % DRI Mean ±SD % DRI
Energy (kcal) 110 58 98 155 90
Total dietary fiber (g) 2.9 ±0.2 12 5.2 ±0.1 21 2.8 ±0.8 11 11 ±1 45 4.3 ±0.5 17
Magnesium (mg) 22 ±1 6 10 ±1 3 14 ±4 4 65 ±1 17 20 ±4 5
Iron (mg) 0.70 ±0.04 5 0.45 ±0.13 3 0.37 ±0.03 3 3.17 ±0.91 23 0.83 ±0.24 6
Zinc (mg) 0.34 ±0.13 3 0.25 ±0.11 3 0.23 ±0.02 2 1.70 ±0.58 17 0.29 ±0.05 3
Potassium (mg) 757 ±118 22 294 ±138 8 291 ±107 8 783 ±25 22 327 ±26 9
Sodium (mg) 856 ±26 43 843 ±152 42 891 ±177 45 825 ±205 41 713 ±36 36
Vitamin A (µg RAE) 331 ±3 15 NA 422 ±3 11 NA 28 ±5 14
Lycopene (mg) 11.3 ±0.8 NA NA NA NA
Lutein (mg) 0.14 ±0.01 NA 0.46 ±0.00 NA NA
Thiamine (mg) 0.07 ±0.03 7 0.13 ±0.06 12 0.04 ±0.02 3 0.19 ±0.02 17 0.05 ±0.03 5
Riboflavin (mg) 0.13 ±0.02 9 0.07 ±0.05 5 0.07 ±0.00 5 0.18 ±0.08 13 0.07 ±0.01 5
Niacin (mg) 1.47 ±0.07 9 0.46 ±0.30 3 0.70 ±0.13 4 1.65 ±0.70 10 0.89 ±0.21 6
Pantothenic acid (mg) 0.18 ±0.05 3 0.14 ±0.05 2 0.21 ±0.03 3 0.46 ±0.18 8 0.21 ±0.03 3
Pyridoxine (mg) 0.09 ±0.00 6 0.07 ±0.01 5 0.09 ±0.02 6 0.18 ±0.04 13 0.12 ±0.04 8
Vitamin C (mg) 15 ±1 18 <LOQ 5<LOQ <LOQ <LOQ
Vitamin K1 (µg) 4.7 ±0.1 6 1.3 ±0.8 2 NA 11.2 ±5.0 15 10.5 ±2.2 14
Nutrient density score 636 34 9 88 36
1
Values are means
±
SD of triplicate measurements of two varieties of each vegetable soup type.
2
DRI =dietary reference intake [
16
].
3
Vitamin A was calculated from analyzed
β
-Carotene values that were converted to retinol activity equivalents.
4
NA =not analyzed. Based on the raw ingredients for these soup types, it was not expected to detect any carotenoids.
5
LOQ =limit of quantification. For vitamin C, this was set at 10 mg/100 g dry soup.
6
Based on total dietary fiber, magnesium, iron, zinc, potassium, vitamin A, thiamin, riboflavin, niacin,
pantothenic acid, pyridoxine, vitamin C, and vitamin K1 as positive nutrients and sodium as a negative nutrient, with the exception that vitamin C was not included in the score for onion,
pumpkin, pulses/legumes, and mixed vegetables; vitamin K1 was not included for pumpkin, and vitamin A was not included for onion and pulses/legumes soups.

Nutrients 2019,11, 1270 7 of 11
3.4. Comparison of Nutrient Density Scores of Dry Vegetable Soups with Home-Made and Other Soups
A total of 125 soups in the USDA and BLS food composition tables met the selection criteria for
comparison with dry vegetable soups; 22 were classified as home-made soups, and 102 were classified
as other soups. The nutrient density score of these soups ranged from 77 to 151. Figure 1shows that
there were no systematic differences between the nutrient density scores of the dried soups and that of
other types of soup. As compared to home-made soups, the nutrient density scores of the dry soups
were relatively low for pumpkin soup and relatively high for onion and pulses/legume soup.
Nutrients 2019, 11, x FOR PEER REVIEW 7 of 11
3.4. Comparison of Nutrient Density Scores of Dry Vegetable Soups with Home-Made and Other Soups
A total of 125 soups in the USDA and BLS food composition tables met the selection criteria for
comparison with dry vegetable soups; 22 were classified as home-made soups, and 102 were
classified as other soups. The nutrient density score of these soups ranged from 77 to 151. Figure 1
shows that there were no systematic differences between the nutrient density scores of the dried
soups and that of other types of soup. As compared to home-made soups, the nutrient density scores
of the dry soups were relatively low for pumpkin soup and relatively high for onion and
pulses/legume soup.
Figure 1. Nutrient density scores of dry vegetable soups with home-made and other soups.
3.5. Fresh Vegetable Equivalent Content of Dry Vegetable Soups
The vegetable powder content of the dry vegetable soups ranged from 9–41 g per serving of 250
mL (Table 4). This is equivalent to 0.9–2.5 portions of fresh vegetables per serving and corresponds
with 29–82% of the daily recommended vegetable intake of 240 g/day. The mean fresh vegetable
equivalent content of the dried soups was 120 g, which corresponds to 1.5 portion equivalents of
vegetables and 50% of the recommended intake.
Table 4. Vegetable content of dry vegetable soups per 250 mL serving.
Soup Variety Dry Vegetable
Content (g)
Weighted Factor to
Account for
Rehydration 2
Mean Fresh Vegetable
Equivalents (g)
Contribution to
Vegetable
Recommendation (%) 3
Tomato 11.9 1 15.9 189 79
Onion 8.9 8.6 77 32
Pumpkin 9.7 10.7 103 43
Pulses/legumes 40.4 3.7 148 61
Mixed vegetable 9.1 9.2 84 35
1 Values are means of two sub varieties of each vegetable soup variety. 2 Factor is a weighted mean of
factors to account of rehydration of the different dried vegetable powders. 3 Based on WHO/FAO of
≥240 g/day [10].
Figure 1. Nutrient density scores of dry vegetable soups with home-made and other soups.
3.5. Fresh Vegetable Equivalent Content of Dry Vegetable Soups
The vegetable powder content of the dry vegetable soups ranged from 9–41 g per serving of
250 mL (Table 4). This is equivalent to 0.9–2.5 portions of fresh vegetables per serving and corresponds
with 29–82% of the daily recommended vegetable intake of 240 g/day. The mean fresh vegetable
equivalent content of the dried soups was 120 g, which corresponds to 1.5 portion equivalents of
vegetables and 50% of the recommended intake.
Table 4. Vegetable content of dry vegetable soups per 250 mL serving.
Soup Variety Dry Vegetable
Content (g)
Weighted Factor to
Account for
Rehydration 2
Mean Fresh Vegetable
Equivalents (g)
Contribution to
Vegetable
Recommendation (%) 3
Tomato 11.9 115.9 189 79
Onion 8.9 8.6 77 32
Pumpkin 9.7 10.7 103 43
Pulses/legumes 40.4 3.7 148 61
Mixed vegetable 9.1 9.2 84 35
1
Values are means of two sub varieties of each vegetable soup variety.
2
Factor is a weighted mean of factors to
account of rehydration of the different dried vegetable powders. 3Based on WHO/FAO of ≥240 g/day [10].

Nutrients 2019,11, 1270 8 of 11
4. Discussion
This study aimed to measure the nutritional composition of dry vegetable powder and soups and
to compare the nutrient density scores of dry vegetable powders with that of published data from
respective fresh and cooked vegetables and home-made and industrially prepared soups. Our data
indicate that the nutritional quality of dry vegetable powders is of similar magnitude as that of
cooked vegetables. As a consequence, dried vegetable soups made from these powders can, like other
types of vegetable soups, significantly contribute to the recommended daily intake of fibers, minerals,
and vitamins.
Our study provides new data on the nutritional composition, including fiber, 13 micronutrients,
and sodium of different dried vegetable soups, by using validated methods. We compared these
new data against a substantial amount of data from home-made and industrially prepared soups
in USDA and BLS food composition tables. A limitation is the explorative design of our study;
due to scarce and heterogenous published data, we could not formulate a quantitative hypothesis
on the differences between the nutrient composition of dry vegetable powders and soups and that
of respective fresh and cooked vegetables and other soups. To confirm our observations, a more
comprehensive sampling methodology and statistical approach to address variation in factors that
influence the nutritional quality would be needed. Due to practical constraints, we had to use different
methodologies to compare the nutrient content and nutritional quality of the different vegetables and
soups (i.e., analyzed data for the dry vegetable powders and soups versus published data of fresh
and cooked vegetables and other soups). For example, fiber content was considerably higher in our
dry vegetable soups than that of respective products in the food composition tables, which may be
explained by differences in methodology of analyses and in fiber definitions. Furthermore, we had to
discard some of the nutrient content data due to failure of analyses—the unexpected high and highly
variable folate levels in the soups due to influence of lipids in the soup matrix on the assay, for instance.
A method based on HPLC-DAD-MS for quantifying individual folate homologues that we have used
to measure nutrient the retention of folate during soup preparation in a separate study yielded more
reliable results (see Supplemental data S2) and may be recommended for the analysis of folate in dry
soups in the future.
We used nutrient density scores as a marker for the nutritional quality of the soups and vegetables.
It should be noted that these scores cannot be directly related to impact on nutrition and health.
For example, the food matrix in which the nutrients are present and form of the product (e.g., fresh,
dried, or composite food) could influence the bioaccessibility and bioavailability of the nutrients and,
subsequently, impact health [
20
]. Therefore, the nutrient density scores should rather be used to rank
foods within a food category—to compare nutritional quality of different preparation forms (dried,
fresh, and cooked) of a specific product or food (in this case vegetable powders and soups), for instance.
In the current study, we found that the nutritional quality of the dry vegetable powders was generally
similar to that of cooked vegetables, as well as for the fresh equivalent, in the case of onion. In contrast,
the nutrient density scores for cooked and fresh tomato were considerably higher than for dry tomato
powder due to the relatively high vitamin C level in cooked tomato. When vitamin C was not included
in the nutrient density score calculation, scores for dried tomato (255) and for cooked tomato (219–431)
were of similar range.
The nutrient content of vegetable crops is determined by many factors, including the type of soil
(e.g., pH, water holding capacity, porosity, cation exchange capacity, and mineral composition),
climate (e.g., light intensity, temperature, and rainfall), crop variety, management practices
(e.g., pesticides and fertilizers), maturity, postharvest handling, and storage [
21
]. Differences in
one or more of these factors may explain part of the variation in the nutritional quality within and
between the differently processed vegetables in our study. A comparison of dried, cooked, and fresh
vegetables that are grown, harvested, and stored under the same circumstances would be needed to
confirm our findings.

Nutrients 2019,11, 1270 9 of 11
Our study shows that dry soups made of lentils and pulses deliver almost twice the amounts of
micronutrients as compared to the other dry soups. This was also reflected in the nutrient density
scores. Though most of the nutrients that were measured in the dried vegetable soups most likely
originate from the dried vegetable powders, we found considerably higher levels for some of the B
vitamins than what would be expected from the soups’ vegetable contents. We assume that these
higher levels may be attributed to added yeast extract, as this ingredient has been reported to be
particularly rich in thiamin, riboflavin, and niacin [
22
–
24
]. Similarly, the higher potassium levels in
tomato and onion soups may be explained by added potassium chloride as a salt-replacing ingredient.
Vitamin C could only be detected in dried tomato soups, which contained 18% DRI. It is known
that vitamin C is heat-labile, and major losses are expected during cooking. In order to obtain
better insights in nutrient retention during the drying and cooking processes of dried and equivalent
home-made soups, we performed an additional study on the retention of a number of key nutrients
in tomato, onion, and lentil soups (see Supplementary Material S2 and Figure S1 for methods and
results). This retention study showed that 43% of vitamin C levels in dried tomato soups were retained
during cooking, similar to home-made tomato soups, in which 36% of vitamin C levels were retained.
For lycopene, folate, and potassium (data not shown) there was also no clear differences in nutrient
retention between the prepared dried vegetable soups and home-made soups. This is confirmed by
our finding that nutrient density scores of the analyzed dried soups had nutrient density scores in the
same range as those of home-made and other soups based on data from FCTs.
Our data also shows that the dried vegetable soups can contain between 1–2.5 portion equivalents
of vegetables, thereby contributing to 30–80% of the daily vegetable recommendation of 240 g/day.
Furthermore, we found that most of the fiber and nutrients from the vegetable ingredients remain
present in the dried soups and that the nutrient density of dried soups is similar to that of home-made
and other vegetable soups. However, as soups also contribute significantly to sodium intake (36–45%
of the daily recommendation in one serving), soup consumption should be kept within limits of dietary
guidelines, and efforts should be made to lower the sodium content of soups.
Lastly, health authorities are increasingly shifting their recommendations towards healthy and
sustainable diets with an emphasis to consume more plant-based foods, such as fruits, vegetables,
whole grains, and pulses [
25
]. Drying is a process to preserve foods with the potential to increase the
plant-based food supply worldwide by preventing post-harvest losses. A recent study showed that,
on a per serving basis, dried soups are more environmentally sustainable compared to wet soups,
mainly because dried products have a lower mass and therefore require less packaging and are more
efficient to transport [
26
]. While dried products such as dry vegetable soups may be perceived by
consumers to be of low nutritional quality, data from the current study indicate that dried vegetable
soups can be as nutritious as home-made soups, and, as such, could help to increase vegetable intake
and fit in a healthy and sustainable diet.
In conclusion, the nutritional value of dry vegetable soups does not seem different from that
of home-made soups. Dry vegetable soups can be considered a suitable source of vegetables and
nutrients and may deliver a significant part of recommended daily nutrient and vegetable intake.
Supplementary Materials:
The following are available online at http://www.mdpi.com/2072-6643/11/6/1270/s1,
Data S1: Trade names and ingredient composition of soups used in this study, Data S2: Study of retention of
selected marker nutrients in dried and home-made soups, Figure S1: Nutrient retention from fresh vegetable
ingredients to prepared dry and home-made soups.
Author Contributions:
Conceptualization, L.v.B., C.H.G., S.B., M.S., R.N., and A.E.; methodology, L.v.B.,
C.H.G., S.B., and M.S.; formal analysis, L.v.B., C.H.G., R.N., and A.E.; writing—original draft preparation, A.E.;
writing—review and editing, L.v.B., C.H.G., S.B., M.S., R.N., and A.E.
Funding: This research was funded by Unilever.
Acknowledgments:
We would like to thank Peter L. Zock, Unilever R&D Vlaardingen, Netherlands for critical
review of the manuscript.
Conflicts of Interest: All authors are employees of Unilever. Unilever markets foods such as vegetable soups.

Nutrients 2019,11, 1270 10 of 11
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