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Amaranth sprouts and microgreens – a homestead vegetable production option to enhance food and nutrition security in the rural-urban continuum

Authors:
  • Food and Fertilizer Technology Center for the Asian and Pacific Region

Abstract and Figures

Traditional vegetables and vegetable legumes can be a source of readily available daily sustenance when grown in home or kitchen gardens. Lower income groups that lack access to or cannot afford global vegetables and animal protein sources would benefit greatly from the increased availability and consumption of traditional vegetables. Phytonutrient levels of edible parts differ according to the growth stages of the plant and often decrease from the seedling (sprout or microgreen) to the fully developed stage. Sprouts and microgreens can easily be grown in urban or peri-urban settings where land is often a limiting factor, either by specialized vegetable farmers or the consumers themselves. Given their short growth cycle, sprouts and microgreens can be grown without soil and without external inputs like fertilizers and pesticides, around or inside residential areas. Seedlings from semi-domesticated or even wild species typically have high levels of phytonutrients, good flavor, and tender texture. Several crops or different varieties of the same crop can be mixed to create attractive combinations of textures, flavors, and colors. As sprouts and microgreens are usually consumed raw, there is no loss or degradation of heat-sensitive micronutrients through food processing. AVRDC is currently studying potential differences in the levels of essential micronutrients, bioactive compounds, and consumer preferences of selected traditional vegetables and vegetable legumes at different growth and consumption stages. The results obtained with amaranth are reported in this paper. Amaranth is increasingly becoming popular as a nutrient-dense leafy green beyond Asia and the Caribbean (Saelinger 2013). The phytonutrient content was assessed at three stages: (a) sprouts, (b) microgreens, and (c) fully grown plants. The comparison included landraces from the AVRDC Genebank and commercially available cultivars. This work may expand the use of genebank materials for specialty produce such as sprouts and microgreens with great potential to improve food and nutrition security for people living in urban and peri-urban settings.
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Amaranth sprouts and microgreens a
homestead vegetable production option to
enhance food and nutrition security in the rural-
urban continuum
Ebert, A.W.
AVRDC THE WORLD VEGETABLE CENTER, P.O. BOX 42, SHANHUA, TAINAN 74199, TAIWAN
Andreas.ebert@worldveg.org
Wu, T.H.
AVRDC THE WORLD VEGETABLE CENTER, P.O. BOX 42, SHANHUA, TAINAN 74199, TAIWAN
Tien-hor.wu@worldveg.org
Yang, R.Y.
AVRDC THE WORLD VEGETABLE CENTER, P.O. BOX 42, SHANHUA, TAINAN 74199, TAIWAN
Ray-yu.yang@worldveg.org
ABSTRACT
Traditional vegetables and vegetable legumes can be a source of readily available
daily sustenance when grown in home or kitchen gardens. Lower income groups that
lack access to or cannot afford global vegetables and animal protein sources would
benefit greatly from the increased availability and consumption of traditional
vegetables. Phytonutrient levels of edible parts differ according to the growth stages
of the plant and often decrease from the seedling (sprout or microgreen) to the fully
developed stage. Sprouts and microgreens can easily be grown in urban or peri-urban
settings where land is often a limiting factor, either by specialized vegetable farmers
or the consumers themselves. Given their short growth cycle, sprouts and microgreens
can be grown without soil and without external inputs like fertilizers and pesticides,
around or inside residential areas.
Seedlings from semi-domesticated or even wild species typically have high
levels of phytonutrients, good flavor, and tender texture. Several crops or different
varieties of the same crop can be mixed to create attractive combinations of textures,
flavors, and colors. As sprouts and microgreens are usually consumed raw, there is no
loss or degradation of heat-sensitive micronutrients through food processing. AVRDC
is currently studying potential differences in the levels of essential micronutrients,
bioactive compounds, and consumer preferences of selected traditional vegetables and
vegetable legumes at different growth and consumption stages.
The results obtained with amaranth are reported in this paper. Amaranth is
increasingly becoming popular as a nutrient-dense leafy green beyond Asia and the
Caribbean (Saelinger 2013). The phytonutrient content was assessed at three stages: (a)
sprouts, (b) microgreens, and (c) fully grown plants. The comparison included
landraces from the AVRDC Genebank and commercially available cultivars. This
work may expand the use of genebank materials for specialty produce such as sprouts
and microgreens with great potential to improve food and nutrition security for people
living in urban and peri-urban settings.
Keywords
Traditional vegetables, sprouts, microgreens, food and nutrition security, rural-urban
continuum
Sustaining Small-Scale Vegetable Production and Marketing Systems for Food and Nutrition Security 233
INTRODUCTION
Diet-related diseases such as obesity, diabetes, cardiovascular disease, hypertension,
stroke, and cancer are escalating both in developed and developing countries, in part
due to imbalanced food consumption patterns. Health experts are convinced of the
multiple benefits of consuming vegetables and fruit on a regular basis and the World
Health Organization recommends that people eat at least 400 grams of fruit and
vegetables a day (WHO/FAO 2005), while the World Cancer Research Fund would
like to see the consumption of fruit and non-starchy vegetables to beat least 600 grams
per day (WCRF/AICR 2007). Based on a published meta-analysis of nutritional
epidemiology studies it was estimated that approximately 20,000 cancer cases per
year could be prevented in the U.S. by increasing fruit and vegetable consumption by
160 g/person/day (Reiss et al. 2012). Another large study conducted by Boffetta et al.
(2010) included nearly half a million persons in Europe and covered all cancer types.
The authors concluded that with an average increase of fruit and vegetable
consumption of approximately 150 g/d, 2.6% cancers in men and 2.3% cancers in
women could be avoided. Looking at specific cancers for which there is good
evidence for a benefit from fruit and vegetable consumption, the cancer avoidance
effect could be much higher.
One of the most valuable benefits of traditional leafy vegetables is their high
content of vitamins, minerals, fiber and other micronutrients essential for human
health. Many traditional vegetables contain high levels of β-carotene and vitamin C,
and in general have higher vitamin E, folate, calcium, iron, and zinc content and
higher antioxidant activity compared with global vegetables (Yang and Keding 2009).
Including traditional vegetables in the diet has great potential to combat malnutrition
and improve overall health. Lower income groups for whom traditional vegetables are
more affordable than common global vegetables or animal meat products will benefit
greatly from increased availability and consumption of traditional vegetables.
The high nutritional value of many traditional fruits and vegetables has inspired
Unilever to assemble a scientific consortium to identify ‘pre-domesticated’ varieties
of crops (mainly fruits and vegetables) that have been changed very little by breeding
and might contain significantly higher levels of nutrients than the varieties currently
used for food production (Unilever 2012). This conclusion is supported by a review
study conducted on 43 garden crops based on United States Department of
Agriculture (USDA) food composition data, which revealed a statistically reliable
decline of six nutrients (protein, Ca, P, Fe, riboflavin and ascorbic acid) between 1950
and 1999 (Davis et al. 2004). These changes might be due to the replacement of older,
more nutritious cultivars with modern ones. Similar trends have been observed in
wheat grain (Garvin et al. 2006; Fan et al. 2008) and potato tubers (White et al. 2009).
Breeding and selection for high yield may have led to a decline in some essential
nutrients.
Phytonutrient levels differ according to the growth stages of the plant and often
decrease from the seedling (sprout, microgreen) to the fully developed stage (van
Hofsten 1979; Barillari et al. 2005; Nakamura et al. 2001; Ebert 2013a,b). In addition
to their high nutritional value, microgreens are considered functional foods with
particular health-promoting or disease-preventing properties (Samuoliene et al. 2012).
Sprouts and microgreens can be easily produced in urban or peri-urban settings where
land is often a limiting factor, either by specialized vegetable farmers or the
consumers themselves. Given their short growth cycle, sprouts and microgreens can
be grown without soil and without external inputs like fertilizers and pesticides,
around or inside residential areas. Moreover, sprouts and microgreens are usually
234 SEAVEG2014: Families, Farms, Food
consumed raw, hence there is no loss or degradation of micronutrients through food
processing.
Through a new project funded by the Council of Agriculture of Taiwan, AVRDC
is studying the levels of essential micronutrients and consumer preferences of selected
legume crops (mungbean, soybean) and traditional vegetables (amaranth, mustard,
radish) at different growth and consumption stages: (a) sprouts; (b) microgreens -
seedlings harvested when the first true leaves appear, and (c) fully grown plants at the
usual consumption stage. All five crops are well represented in AVRDC’s genebank.
The comparison included landraces from the AVRDC genebank and modern cultivars
available commercially. Due to the large amount of data, the results reported in this
paper are limited to amaranth.
MATERIALS AND METHODS
Plant materials and growing conditions
The following amaranth genebank accessions and commercial lines were used for the
experiments:
1. VI044470: Genebank accession; species: Amaranthus tricolor; cultivar
/pedigree: Ames 5134; origin: USA; acquisition date: March 1995.
2. VI047764: Genebank accession; species: A. tricolor; cultivar /pedigree: Lal
Shak; origin: Bangladesh; acquisition date: June 2000.
3. Juan-Chih-Shing’: Commercial line; purchased in June 2013 from local market
in Tainan City, Taiwan.
4. Hung-Shing-Tsai: Commercial line; purchased in June 2013 from local market
in Tainan City, Taiwan.
For the production of amaranth sprouts, seeds were soaked for 9 hours in
distilled water, followed by rinsing. Seeds were then placed in a single layer on paper
cloth inside perforated plastic trays, which were enclosed in solid plastic boxes for
drainage of excess water and to maintain high moisture content for sprout growth. The
boxes were kept at room temperature at 26±2oC. The seedlings were carefully watered
twice daily. Plant samples were harvested in three replicates at 7 days after sowing for
nutritional analysis (Table 1). Another sample was taken at 8 days after sowing for
consumer assessment of the produce.
For microgreen production, a mixture of peat moss and vermiculite at a 3:1 ratio
was used as substrate. Seed was mixed with sand and broadcast in plastic trays. The
substrate was kept moist and the plastic trays were placed on benches inside a
greenhouse with a water wall and fan to keep temperatures in the range of 26±2oC.
Plant samples were harvested in three replicates at 9 days after sowing for nutritional
analysis and consumer assessment (Table 1).
For open field production, seeds were broadcast in field plots at the beginning of
October and harvested at the full vegetative growth stage (28 days after sowing) for
nutritional analysis and consumer evaluation (Table 1).
Sustaining Small-Scale Vegetable Production and Marketing Systems for Food and Nutrition Security 235
Consumer evaluation
Plant samples were assessed at three growth/consumption stages (sprouts,
microgreens, fully grown leafy vegetable) for consumer evaluation of sensory aspects,
such as appearance, color, texture, aroma, sweetness, bitterness, taste, and general
acceptability. Each parameter was rated on a scale from 1-5 with the following
attributes: 1 = dislike extremely; 2 = dislike slightly; 3 = neither like nor dislike; 4 =
like slightly; 5 = like extremely. Volunteers composed of AVRDC employees and
their relatives, trainees and students rated the produce. Sprouts were rated by 53
consumers (36 female; 17 male), microgreens by 34 consumers (23 female; 11 male)
and fully grown leafy amaranth by 53 consumers (37 female; 16 male).
For statistical analysis of the consumer acceptance data, Friedman’s two-way
nonparametric ANOVA was used. The least squares means were adjusted for multiple
comparisons of the acceptance rank means of the test varieties using Tukey’s
Honestly Significant Difference (HSD) test.
Nutritional analysis
About 100-200 g of sprouts, 100-200 g of microgreens and at least 600 g of fully
grown plants of each vegetable variety were sent to the AVRDC nutrition laboratory
for sample preparation and nutritional analysis. Plant samples were cleaned with
distilled water and surface water was removed; plant parts were cut and mixed
thoroughly for sampling. Samples were weighed, freeze dried, ground into fine
powder and stored at -20 oC for subsequent analyses.
The protein content was measured with micro-Kjeldahl digestion followed by
distillation method (AOAC 1990a). The determination of calcium, iron and zinc
contents was performed by ashing procedure, strong acid washing, followed by
Atomic Absorption Spectroscopy (AOAC1990b). The determination of total ascorbic
acid was carried out as described by Hanson et al. (2004) on the basis of coupling 2,4-
dinitrophenylhydrazine (DNPH) with the ketonic groups of dehydroascorbic acid
through the oxidation of ascorbic acid by 2,6-dichlorophenolindophenol (DCPIP) to
form a yellow-orange color in acidic conditions. Carotenoids including a-carotene, β-
carotene, neoxanthin, and lutein were analyzed using high performance liquid
chromatography (HPLC) (Hanson et al. 2004). Simple phenolic acids including
caffeic acid, chlorogenic acids and flavonoids were analyzed using HPLC as
described by Yang et al. (2008). Carotenoids, phenolic acids and flavonoids were
identified and quantified with commercial standards. Antioxidant activity was
measured using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS)
radical (Re et al. 1999) and expressed as Trolox equivalent (TE). Details were
described by Yang et al. (2006).
RESULTS AND DISCUSSION
Consumer evaluation of amaranth sprouts, microgreens and fully grown
leafy amaranth
Sprouts of genebank accession VI044470 from USA (variety 1) and commercial
cultivar ‘Juan-Chih-Shingfrom Taiwan (variety 3) were consistently preferred by
consumers in terms of appearance, texture and taste as well as general acceptability
(Fig. 1). High scores for taste and general acceptance were also given for the second
commercial cultivar ‘Hung-Shing-Tsai’ from Taiwan.
Microgreens of genebank accession VI047764 from Bangladesh were highly
appreciated in terms of appearance, but disappointing in terms of texture, taste and
236 SEAVEG2014: Families, Farms, Food
general acceptability (Fig. 2). Genebank accession VI044470 and commercial cultivar
Hung-Shing-Tsai received the highest rating for texture, taste and general
acceptability.
Genebank accession VI044470 and Juan-Chih-Shing’ consistently received
highest ratings for appearance, texture, taste and general acceptability at the fully
grown stage (Fig. 3). These same two varieties were clearly preferred at the sprouting
stage as well. Only at the microgreen stage did the second commercial cultivar Hung-
Shing-Tsaireceive slightly better ratings.
Significant differences among the four varieties were detected at all three growth
stages with regard to different parameters such as appearance, taste, texture and
general acceptability, indicating that consumers were able to perceive differences in
sensory attributes.
Nutritional analysis of amaranth sprouts, microgreens and fully grown
leafy amaranth
Mean dry matter and protein content was highest in fully grown leafy amaranth,
followed by amaranth sprouts, while—surprisingly—amaranth microgreens had the
lowest dry matter and protein content (Tables 2,4,6), although they were grown for
nine days compared with sprouts grown for seven days only. Among 25 types of
microgreens assessed by Xiao and co-workers (2012), garnet amaranth microgreens
showed a relatively high dry weight percentage of 9.3, much closer to the dry matter
content determined for fully grown leafy amaranth and amaranth sprouts in our trials.
Mean protein, Fe and Zn content was also considerably higher in amaranth
sprouts compared with amaranth microgreens (Tables 2,4). Only the mean calcium
content of amaranth microgreens was 1.6-fold higher than that in amaranth sprouts.
Microgreens of the genebank accession VI044470 and commercial cultivar Hung-
Shing-Tsaihad the highest calcium levels (Table 4). The zinc content of amaranth
sprouts of three varieties was almost identical, only accession VI044470 presented a
lower content (Table 2). Sprouts of Juan-Chih-Shing’ and Hung-Shing-Tsai
presented the highest iron and calcium content, respectively. Zinc content of amaranth
leaves at fully grown stage was similar to that in amaranth sprouts, while iron and
calcium content was 1.9-fold and 7.8-fold higher, respectively (Tables 2,6).
Compared with microgreens, calcium content was still 5-fold higher in fully grown
amaranth leaves (Tables 4,6).
Vitamin C or ascorbic acid is an essential nutrient for the human body—it is
required for the biosynthesis of collagen, carnitine and neurotransmitters (Naidu
2003). While most plants and animals have the ability to synthesize ascorbic acid,
apes and humans depend on the intake of this essential nutrient through fruit and
vegetables or supplementation in the form of tablets. Health benefits attributed to
vitamin C include antioxidant, anti-aetherogenic, anti-carcinogenic, and
immunomodulator effects. Rose and Bode (1993) mention three principal reasons that
enable ascorbate to assume a prominent role as scavenger of free radicals in the
human body: (a) it is chemically suited to react with oxidizing free radicals; (b) it is
present in the body at sufficiently high concentrations to be effective; (c) it fits into
the physiology of cellular transport and metabolism, and thus contributes to the
potential for longevity. The recommended daily allowances (RDA) for adults are 90
mg of ascorbic acid per day for men and 75 mg for women (Frei and Traber 2001).
Based on clinical and epidemiological studies reduced incidence of mortality from
heart diseases, stroke and cancer can be expected with a dietary intake of 100 mg
ascorbic acid per day (Carr and Frei 1999).
Sustaining Small-Scale Vegetable Production and Marketing Systems for Food and Nutrition Security 237
There was a substantial increase in vitamin C content from amaranth sprouts to
microgreens (2.7-fold) and from amaranth microgreens to fully grown leafy amaranth
(2.9-fold) (Tables 3,5,7). Consuming 100 g of leafy amaranth at the fully grown stage
would provide 79% of RDA for women. There were statistical differences among
varieties at the sprout stage and both genebank accessions had the highest vitamin C
content (Table 3). At the microgreen and fully grown stage no statistical difference
among varieties was noted. Much higher (6.5-fold) total ascorbic acid concentrations
were detected by Xiao et al. (2012) in commercially grown garnet amaranth
microgreens compared with the concentrations found in our experiments. Among 25
commercially grown microgreen crops, amaranth had the second highest total
ascorbic acid content (131.6 mg/100 g FW) after red cabbage in the trials conducted
by the aforementioned authors. These vitamin C concentrations are much higher than
those commonly reported for mature amaranth leaves ranging from 11.6-45.3 mg/100
g FW (Punia et al. 2004; Mensah et al. 2008). The USDA National Nutrient Database
for Standard Reference, Release 23 indicated a vitamin C content of 43.3 mg and 41.1
mg per 100 g FW of edible portion of raw and cooked amaranth leaves, respectively
(Ebert et al. 2011), thus falling within the range reported by Punia et al. (2004) and
Mensah et al. (2008). Mean vitamin C content of fully grown amaranth leaves
reached 59 mg in our trials, thus slightly above the aforementioned levels.
Higher plants exhibit a relatively uniform carotenoid composition and a small
number of carotenoids, i.e., the β-carotene, the xanthophylls lutein and neoxanthin as
well as those involved in the xanthyphyll cycle (violaxanthin, antheraxanthin, and
zeaxanthin), which are ubiquitously present in the photosynthetic membranes of
higher plants (Young 1993). The α-carotene is less frequent, but can also be found in
a number of plant species. Both, α-carotene and β-carotene are called provitamin A as
they can be easily converted by the human body into vitamin A, which is important
for maintenance of visual acuity. Carotenoids are the first line of defense against
photo-oxidative stress in plants, given their capacity to quench singlet oxygen as well
as triplet chlorophylls through a physical mechanism involving transfer of excitation
energy followed by thermal deactivation (Ramel et al. 2012). Another mechanism is
known as chemical quenching and involves a chemical reaction between the quencher
and singlet oxygen.
Both provitamins A (α-carotene and β-carotene) were detected in all three
developmental stages and considerably increased from sprouts to microgreens (Tables
3,5). Microgreens of the genebank accession VI044470 had the highest α-carotene
and β-carotene content. The level of α-carotene of microgreens of this accession was
higher than those found in mature amaranth leaves, while the β-carotene content was
similar in microgreens and mature leaves. The β-carotene content of amaranth
microgreens reported earlier was 4.6-fold higher (8.6 mg/100 g FW) than found in our
experiments and red sorrel microgreens showed even higher β-carotene content of up
to 12.1 mg/100 g FW (Xiao et al. 2012).
Violaxanthin, a natural orange-colored carotenoid found in photosynthetic
organs of plants, was analyzed in amaranth sprouts but found to be below detectable
levels. It reached 0.91 and 1.75 mg/100 g FW in amaranth microgreens and fully
grown amaranth leaves, respectively (Tables 5,7)—again much lower than the
violaxanthin levels (4.4. mg/100 g FW) reported by Xiao et al. (2012). Neoxanthin
was found at all three growth stages, with substantially higher levels at the microgreen
and fully grown stage compared to amaranth sprouts (Tables 3,5,7).
Lutein and zeoxanthin are macular pigments that act as optical filters and play a
critical role in the prevention of age-related macular degeneration (Beatty et al. 1999).
238 SEAVEG2014: Families, Farms, Food
Macular pigment is entirely of alimentary origin and its density can be augmented
through dietary modification. Apart from restricting photochemical retinal injury by
screening blue light, macular pigment might also play a role in limiting oxidative
damage by quenching reactive oxygen species. The lutein content increased
substantially from amaranth sprouts to microgreens (2.18 mg/100 g FW), but was still
slightly lower in the latter compared to fully grown amaranth leaves (Tables 3,5,7).
These concentrations are again in contrast to the findings of Xiao et al. (2012), who
reported 8.4 mg/100 g FW of lutein/zeoxanthin in amaranth microgreens.
Microgreens of genebank accession VI044470 and cultivar Hung-Shing-Tsai
showed the highest lutein and neoxanthin content (Table 5).
Highly reactive free radicals and oxygen species are inevitably produced in
biological systems and are also encountered exogenously. They may oxidize nucleic
acids, proteins, lipids or DNA and are known to cause various degenerative disorders,
such as Alzheimer’s disease, Parkinson’s disease, cardiovascular disturbances, cancer,
and aging (Prakash et al. 2001; Uttara et al. 2009). Antioxidants are considered a
persuasive therapeutic option to combat neurodegenerative diseases given their
capability to neutralize free radicals. Fruits, vegetables and herbs contain a wide range
of antioxidants comprising phenolic compounds, such as phenolic acids, flavonoids,
quinons, coumarins, lignans, tannins, etc.; nitrogen compounds, such as alkaloids,
amines, betalains, etc.; vitamins; terpenoids including carotenoids and other
endogenous compounds that have a high antioxidant activity (Uttara et al. 2009;
Samuoliene et al. 2012). The antioxidant activity is commonly expressed in
micromoles of Trolox equivalents (TE) per 100 g (Prakash et al. 2001).
Surprisingly, the antioxidant activity (AOA) of amaranth sprouts was much
higher than that of amaranth microgreens and was highest in fully grown leaves
reaching 1924 µmol TE with variety ‘Hung-Shing-Tsai’ (Tables 3,5,7). While sprouts
of genebank accession VI044470 had a relatively low AOA, the other three varieties
had a high AOA ranging from 1355 TE to 1491 TE—about double the antioxidant
activity measured in amaranth microgreens, on average. Microgreens of VI044470
showed only a slight decrease in AOA compared with sprouts, in contrast to the other
three varieties.
Hydroxycinnamic acid compounds are an important source of antioxidants and
are usually found as esters of organic acid or glycosides in plants or are bound to
protein and cell wall polymers (Chen and Ho 1997). These compounds, which include
caffeic acid and chlorogenic acid, have a significant effect on stability, color, flavor
and nutritional value of food. Caffeic acid concentration notably increased from
amaranth sprouts to microgreens to fully grown amaranth leaves (Tables 3,5,7).
Chlorogenic acid was detected only in microgreens of genebank accession VI047764
and was below detectable levels in the other three varieties. Chlorogenic acid was not
detected in amaranth sprouts and fully grown leaves.
SUMMARY AND CONCLUSION
Genebank accession VI044470 and commercial cultivar ‘Juan-Chih-Shing
consistently received the highest ratings for appearance, texture, taste and general
acceptability at the sprout and at the fully grown stage. At the microgreen stage,
VI044470 and ‘Hung-Shing-Tsaireceived the highest ratings.
The phytonutrient content showed significant differences among varieties within
the same growth stage and also differed between growth stages. Mean protein, Fe and
Zn content was considerably higher in amaranth sprouts compared with amaranth
microgreens. There was a substantial increase in vitamin C content from amaranth
Sustaining Small-Scale Vegetable Production and Marketing Systems for Food and Nutrition Security 239
sprouts, to microgreens (2.7-fold) and from amaranth microgreens to fully grown
leafy amaranth (2.9-fold). Both provitamins A, α-carotene and β-carotene were
detected in all three developmental stages and considerably increased from sprouts to
microgreens. The content of α-carotene was the same at the microgreen and fully
developed stage, while β-carotene content was slightly higher at the latter stage.
Sprouts and microgreens offer a niche market for vegetable producers and can
easily be grown by consumers themselves, especially in urban or peri-urban settings,
providing a constant, year-round source of easily accessible, fresh and nutrient-dense
produce and serving as educational and therapeutic tool for children in the homestead.
Given their extremely short growth cycle, sprouts and microgreens can easily be
grown organically, without external inputs like fertilizers and pesticides.
Acknowledgement
The authors would like to acknowledge the technical support provided by Sheng-hung
Yen, Genetic Resources and Seed Unit, and Ching-Yu Shih, summer student from
National Chung Hsing University, Taiwan (July to August 2013) for conducting part
of the amaranth experiments reported here.
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Table 1. Timetable for production and harvesting of amaranth sprouts, microgreens and fully
grown leafy amaranth in 2013
Dates
Sprouts
Microgreens
Fully grown stage
Sowing for nutritional analysis
3 July 2013
2 July 2013
1 October 2013
Harvesting of samples for
nutritionalanalysis
10 July 2013
11 July 2013
29 October 2013
Sowing for consumer evaluation
18 July 2013
2 July 2013
1 October 2013
Harvesting of samples for consumer
evaluation
26 July 2013
11 July 2013
29 October 2013
Consumer evaluation
26 July 2013
12 July 2013
29 October 2013
Table 2. Dry matter, protein and minerals of amaranth sprouts per 100 g edible portion of fresh
weight
Accession/cultivar
Dry matter
(g)
Protein
(g)
Ca (mg)
Fe (mg)
Zn (mg)
VI044470
6.13b
1.91b
48.60c
0.92c
0.43b
VI047764
8.80a
2.19ab
27.82d
1.17bc
0.52a
Juan-Chih-Shing
8.64a
2.31a
60.85b
1.68a
0.53a
Hung-Shing-Tsai
8.98a
2.42a
71.33a
1.47ab
0.52a
Mean
8.14
2.21
52.15
1.31
0.50
Values within a column with different letters are significantly different at P< 0.05.
Sustaining Small-Scale Vegetable Production and Marketing Systems for Food and Nutrition Security 241
Table 3. Carotenoid, vitamin C, antioxidant activity (AOA) and caffeic acid content of amaranth
sprouts per 100 g edible portion of fresh weight
Accession /
cultivar
Carotenoids
Vitamin
C (mg)
AOA
(µmol TE)
Caffeic
acid
(µmol)
Violaxanthin
(mg)
Neoxan-
thin
(mg)
Lutein
(mg)
α-
carotene
(mg)
β-
carotene
(mg)
VI044470
0.00
0.04a
0.46a
0.01a
0.10a
8.00a
823.00b
4.95a
VI047764
0.00
0.03a
0.43a
0.01a
0.11a
9.98a
1442.00a
4.79a
Juan-Chih-Shing
0.00
0.02b
0.38a
0.01a
0.11a
5.00b
1355.33a
5.26a
Hung-Shing-Tsai
0.00
0.02b
0.45a
0.01a
0.10a
7.00ab
1490.67a
5.92a
Mean
0.00
0.03
0.43
0.01
0.10
7.59
1277.67
5.23
Values within a column with different letters are significantly different at P< 0.05.
Table 4. Dry matter, protein and minerals per 100 g edible portion of fresh weight in amaranth
microgreens
Accession/cultivar Dry matter (g) Protein (g)
Minerals
Ca (mg)
Fe (mg)
Zn (mg)
VI044470
5.33a
1.38ab
91.00a
1.04a
0.34ab
VI047764
4.43c
1.26b
69.33b
0.71a
0.32b
Juan-Chih-Shing
4.70bc
1.35ab
74.33b
0.82a
0.39a
Hung-Shing-Tsai
5.13ab
1.55a
91.33a
1.27a
0.37a
Mean
4.89
1.39
81.50
0.96
0.36
Values within a column with different letters are significantly different at P< 0.05.
Table 5. Carotenoids, vitamin C, antioxidant activity (AOA), chlorogenic acid and caffeic acid
content of amaranth microgreens per 100 g edible portion of fresh weight
Accession /
cultivar
Violaxanthin
(mg)
Neoxan-
thin (mg)
Lutein
(mg)
α-
carotene
(mg)
β-
carotene
(mg)
Vitamin
C (mg)
AOA
(µmol
TE)
Chlorogenic
acid (µmol)
Caffeic
acid
(µmol)
VI044470 0.77c 1.00a 2.66a 0.35a 2.34a 23.33a 639.33bc 0.00b 14.52c
VI047764 0.67c 0.75b 1.95b 0.13c 1.87b 19.00a 567.67c 0.35a 12.89d
Juan-Chih-
Shing
0.99b 0.62b 1.64b 0.10c 1.37c 19.49a 680.33b 0.00b 21.09a
Hung-
Shing-Tsai 1.20a 0.98a 2.66a 0.27b 1.91b 18.67a 782.67a 0.00b 16.79b
Mean 0.91 0.84 2.18 0.21 1.87 20.13 667.50 0.09 16.32
Values within a column with different letters are significantly different at P< 0.05.
Table 6. Dry matter, protein, oxalate and minerals per 100 g edible portion of fresh weight of
amaranth at fully grown stage
Accession/cultivar
Dry
matter
(g)
Protein (g) Oxalate (mg)
Minerals
Ca (mg)
Fe (mg)
Zn (mg)
VI044470
10.65a
2.98a
171.38a
443.54a
2.76a
0.42b
VI047764
8.96b
2.82b
287.27a
337.31c
2.02c
0.56a
Juan-Chih-Shing
9.39b
2.65c
249.07a
401.27b
2.44b
0.60a
Hung-Shing-Tsai
10.88a
3.07a
254.17a
445.18a
2.67ab
0.42b
Mean
9.97
2.88
240.47
406.83
2.47
0.50
242 SEAVEG2014: Families, Farms, Food
Table 7. Content of carotenoids, vitamin C, antioxidant activity (AOA), chlorogenic acid, and
caffeic acid per 100 g edible portion of fresh weight of amaranth at fully grown stage
Accession
/cultivar
Violaxanthin
(mg)
Neoxanthin
(mg)
Lutein
(mg)
α-
carotene
(mg)
β-
carotene
(mg)
Vitamin
C (mg)
AOA
(µmol
TE)
Chlorogenic
acid (µmol)
Caffeic
acid
(µmol)
VI044470 1.43a 0.99ab 2.61a 0.21a 1.16b 56.33a 1815.72ab 0.00 40.51b
VI047764 2.03a 1.51a 4.14a 0.29a 4.45a 56.95a 1604.09b 0.00 39.72b
Juan-Chih-
Shing 1.79a 0.72b 2.21a 0.12a 2.21ab 59.37a 1643.77b 0.00 66.81a
Hung-
Shing-Tsai 1.75a 1.12ab 3.03a 0.22a 2.23ab 63.85a 1923.55a 0.00 49.39ab
Mean 1.75 1.09 3.00 0.21 2.51 59.12 1746.78 0.00 49.11
Values within a column with different letters are significantly different at P< 0.05.a
Columns headed by different letters within each of the four parameters indicate
statistical difference by the LSMEANS/PDIFF at P>0.05
Figure 1. Results of consumer evaluation of amaranth sprouts
Columns headed by different letters within each of the four parameters indicate
statistical difference by the LSMEANS/PDIFF at P>0.05
Figure 2. Results of consumer evaluation of amaranth microgreens
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
GENERAL
ACCEPTABILITY
APPEARANCE TEXTURE TASTE
variety1
variety2
variety3
variety4
a
b
a
a
a
b
a
b
a
bc
a
b
a
b
a
a
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
GENERAL
ACCEPTABILITY
APPEARANCE TEXTURE TASTE
variety1
variety2
variety3
variety4
a
b
ab
a
b
a
ab
b a
b
a
a
a
b
a
a
Sustaining Small-Scale Vegetable Production and Marketing Systems for Food and Nutrition Security 243
Columns headed by different letters within each of the four parameters indicate
statistical difference by the LSMEANS/PDIFF at P>0.05.
Figure 3. Results of consumer evaluation of fully grown leafy amaranth
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
GENERAL
ACCEPTABILITY
APPEARANCE TEXTURE TASTE
variety1
variety2
variety3
variety4
a
b
a
b
a
b
a
b
ab
b
a
b
a
b
a
b
244 SEAVEG2014: Families, Farms, Food
... Out of the estimated 40.5 million people killed by NCDs each year (71% of the annual deaths worldwide), approximately 32.2 million NCD deaths (80%) were attributable to cancers, cardiovascular diseases, chronic Pseudocereals are underutilized food crops that are receiving increasing attention as highly nutritious and functional foods [44]. Among those, amaranth, quinoa, and buckwheat are increasingly becoming popular for sprout and microgreen production [45][46][47][48]. Apart from soybean, peanut (listed under legumes), and mustard (classified here as a vegetable), almond, hazelnut, linseed, sesame, and sunflower are other oilseed crops that one can use for sprouting or microgreen production (Table 1). ...
... In trials conducted at the World Vegetable Center, the consumer acceptance of amaranth (Amaranthus tricolor) landraces, conserved in the Genebank, were compared with commercially available cultivars [45]. A Genebank accession (VI044470) consistently received the highest ratings for appearance, texture, taste, and general acceptability at the sprout, microgreen, and fully grown stages. ...
... capitata), sorrel (Rumex acetosa), and peppercress (Lepidium bonariense), in general, receive a low consumer acceptability score [22,39]. However, rich content in minerals, vitamins, phenolics, and antioxidant activity can also be found in species of more acceptable tastes, such as amaranth, coriander, and Swiss chard [22,25,37,45,69,70]. As shown with the above examples, identifying microgreen species that satisfy both sensory and health attributes at a high degree remains a challenge since acrid taste's acceptability is subject to both inherited and acquired taste factors [22]. ...
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... The significantly higher dry matter content detected in flaxseed sprouts (+30%) compared to microgreens is in accordance with the recent report of Puccinelli et al. [28] on the same species and cultivar, and it was likely due to the progressively higher water absorption during the growth of the seedlings. An increase in the moisture content of flaxseed sprouts following germination was observed also by Wang et al. [26] and, in several amaranth cultivars, by Ebert et al. [37]. Compared to other studies in the literature, the dry matter content of sprouts in our work was higher than that reported by Wang et al. [26,38] and Wu et al. [39], who found a~10% dry matter content regardless of the flaxseed cultivars. ...
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... A comparative overview of specific taxonomical, morphological and nutritional differences in microgreen, sprouts and mature crops/vegetables has been presented and discussed in detail in Table A3. According to a study by (Wojdyło et al., 2020) sprouts are better sources of amino acids, pectins, and sugars than microgreens, however, microgreens were characterized by a high quantity of primary and secondary metabolites like carotenoids, chlorophylls, organic acid content, and low quantities of sugars, exhibiting higher anticholinergic and anti-diabetic activity than sprouts e.g. the amaranth microgreens contain a higher content of a-carotene, b-carotene, violaxanthin, lutein, and neoxanthin compared to its sprouts which have several reported health benefits (Ebert et al., 2014). ...
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... Leaf amaranth, especially A. tricolor, are popular vegetables in Asia. Amaranthus tricolor can be cultivated in open fields, in greenhouses, or in plant factories and can be sold as uprooted small plants or as a microgreen (Ebert et al., 2014). Because of its short rotation time, it fits into crop calendars easily and is a good option when only a short growing window is available. ...
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... According to a study by (Wojdyło et al., 2020) sprouts are better sources of amino acids, pectins, and sugars than microgreens, however, microgreens were characterized by a high quantity of primary and secondary metabolites like carotenoids, chlorophylls, organic acid content, and low quantities of sugars, exhibiting higher anticholinergic and anti-diabetic activity than sprouts e.g. the amaranth microgreens contain a higher content of a-carotene, b-carotene, violaxanthin, lutein, and neoxanthin compared to its sprouts which have several reported health benefits (Ebert et al., 2014). ...
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Considering the well-being cognizance of masses, the microgreens have emerged as the potential therapeutic functional foods for improving the overall health by dietary supplementation. Microgreens have delicate texture, distinctive flavors and exceptional volume of various nutrients accounting for higher neutraceutical benefits compared to their mature counterparts. Mounting interest in microgreens owes not only to their nutritional significance but also to their fascinating organoleptic traits. Many factors like rapid shrinkage of the land resources, lifestyle modification, healthy diet habits, the functional importance of food etc. cumulatively have resulted in increased interest in the microscale production of vegetables for the ready-to-eat market. Augmenting the production of secondary metabolites could provide more nutritional benefits, sensory attributes, and resistance to pests while, sharing many characteristics with sprouts, they are not associated with any foodborne illness. Their production by manipulation of agronomic practices like seeds, growing media, and light quality and biofortification with nutrients may result in nutrient-rich produce. These high-value crops typically characterized by short postharvest life and several pre a-harvest treatments can effectively maintain the shelf life of microgreens. Further, several genetic improvement tools can enhance the availability of bioactive compounds with minimum antinutritional factors. In this review, the comparative overview of the nutritional significance of microgreens with sprouts and their mature counterparts has been discussed. Further, the advances or manipulations in production technologies, the involvement of breeding programmes, and efficient post-harvest technologies to promote cost-effective production and future strategies for maintaining the shelf life and quality of microgreens have been argued.
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Birbirinden farklı özellikteki birçok bitkisel kaynaklı besin, lezzeti arttırmak, görselliği zenginleştirmek ve yemeğe hoş kokular katmak amacıyla mutfaklarda kullanılmaktadır. Yenilebilir çiçekler ve mikro filizler, dünden bugüne değişen yemek pişirme yöntemleri ve sunum şekillerine baktığımızda karşımıza çıkan en belirgin ürün gruplarıdır. Son zamanlarda oldukça ilgi gören bu ürünler, pek çok farklı tür ve özelliktedir. Çiçekler uzun yıllardır doğada var olan ve insanlığın yüzyıllardır çeşitli şekillerde faydalandığı tabiat zenginliklerindendir. Çekici renkleri, hoş kokuları, ferahlatan aromaları, estetik görünümleri ve karakteristik özellikleriyle günümüze kadar farklı amaçlarla kullanılmış ve kullanılma-ya devam etmektedir. Bu özellikleriyle çiçekler, genellikle güzellik ve sağlık alanlarında yaygın kullanımıyla ön plana çıkmaktadır. Bu konuda yazılmış kaynaklar incelendiğinde, dünya üzerinde farklı iklim koşulları ve toprak yapısına göre pek çok türde çiçeğin olduğu söylenebilir. İnsanoğlunun varoluşuyla birlikte farklı türdeki çiçeklerin çeşitli amaçlarla kullanıldığı bilinmektedir. Farklı çiçek türlerinin bu çok yönlü kullanımının insanların beslenme hayatına girmesi uzun zaman almıştır. Çiçeklerin ve diğer yenilebilir aromatik otların mutfaklara girişi yakın tarihe dayanmakta olup, çeşitli yiyecek ve içeceklerde kullanımının başlaması ile günümüze kadar taşınmıştır.
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Turizm pazarındaki vegan nüfusunun artması, turizmin daha sürdürülebilir yaklaşımla ele alınması gerekliliği ve diğer destinasyonların vegan yiyecek turizmine yönelik sundukları imkânlar vegan yiyecek turizminin ön plana çıkmasını sağlamıştır. Bu nedenle, vegan yiyecek turizminin Türkiye’deki mevcut durumunu ve potansiyelini ortaya çıkarmak amacıyla bu çalışma gerçekleştirilmiştir.
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Tomato (Lycopersicon esculentum Mill.) is among the most widely consumed vegetables worldwide and an important source of certain antioxidants (AO) including lycopene, β-carotene, and vitamin C. Improvement of tomato for content of AO and overall antioxidant activity (AOA) could potentially benefit human health in many countries. We evaluated 50 L. esculentum and three L. pimpinellifolium (L.) Mill. entries for contents of lycopene, β-carotene, ascorbic acid, total phenolics, and two assays for antioxidant activity [anti-radical power (ARP) and inhibition of lipid peroxidation (ILP)] for 2 years during the same period in south Taiwan. We detected high levels of genetic diversity for the AO and AOA measured in this study. Group means of the L. pimpinellifolium entries were significantly higher than L. esculentum group means for ARP, ILP, lycopene, ascorbic acid, phenolics, and soluble solids concentration, suggesting that introgression of alleles from L. pimpinellifolium may have potential to improve cultivated tomato for these traits. Ranking of entries for ILP and ARP were consistent between years, particularly for those entries with the highest means and these assays could be adopted by tomato breeders. Results from ILP and ARP assays were highly correlated (r = 0.82**) and it would be unnecessary to use both assays for tomato. Lycopene, β-carotene, ascorbic acid, soluble solids, and total phenolics were all positively correlated with ARP. Among AO, total phenolics content was most closely associated with ARP (r = 0.90**) and ILP (r = 0.83**); this suggests that phenolics make a major contribution to AOA in tomato fruit. Fruit size was negatively correlated with ARP (r = -0.74**) and ILP (r = -0.71**), indicating that combining large fruit size and high AOA will be challenging.
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Recent studies have shown that modern breeding for high yield, visual appearance and long shelf life led to an unintentional decline in taste and the content of essential nutrients in vegetables. AVRDC – The World Vegetable Center is studying whether traditional vegetables are more nutritious than modern varieties and whether early growth stages of these vegetables offer consumers a higher content of phytonutrients.
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In the past few years the analysis of carotenoids has become much more sensitive with the introduction of high-performance liquid chromatography (HPLC), especially with diode-array detection. This has permitted much more accurate determination of the pigment content and composition of photosynthetic organisms. However, as a note of caution, whilst analytical techniques have improved greatly, they still require very careful extraction of the plant material and subsequent careful handling of the isolated carotenoids. Improper practices at this stage can lead to the formation of a number of artifacts (see Chapter 10). Particularly common is the production of the furanoid derivatives from carotenoids that contain 5,6-epoxide groups. Similarly, many workers continue to employ saponification as an obligatory step during the extraction procedure; at the very least this will cause minor losses of the carotenoids present but it may change the whole nature of the extract by removing xanthophyll esters or destroying some carotenoids.
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A method for the screening of antioxidant activity is reported as a decolorization assay applicable to both lipophilic and hydrophilic antioxidants, including flavonoids, hydroxycinnamates, carotenoids, and plasma antioxidants. The pre-formed radical monocation of 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) is generated by oxidation of ABTS with potassium persulfate and is reduced in the presence of such hydrogen-donating antioxidants. The influences of both the concentration of antioxidant and duration of reaction on the inhibition of the radical cation absorption are taken into account when determining the antioxidant activity. This assay clearly improves the original TEAC assay (the ferryl myoglobin/ABTS assay) for the determination of antioxidant activity in a number of ways. First, the chemistry involves the direct generation of the ABTS radical monocation with no involvement of an intermediary radical. Second, it is a decolorization assay; thus the radical cation is pre-formed prior to addition of antioxidant test systems, rather than the generation of the radical taking place continually in the presence of the antioxidant. Hence the results obtained with the improved system may not always be directly comparable with those obtained using the original TEAC assay. Third, it is applicable to both aqueous and lipophilic systems.