1. Effect of damaged starch on acrylamide content of chapattis and pooris
Effect of damaged starch on acrylamide formation in whole wheat flour based indian traditional staples, chapattis and pooris
Mehrajfatema Z. Mullaa, Vikas R. Bharadwajb, Uday S. Annapurea and Rekha S. Singhala
aFood Engineering and Technology Department, Institute of Chemical Technology,
N.P. Marg Matunga, Mumbai , INDIA
bReliable Analytical Laboratories, Manpada,Thane , INDIA
ABSTRACT
INTRODUCTION
Table 2. Impact of additives on pH of the dough, acrylamide formation and sensory analysis of pooris prepared from whole wheat flour containing 28.12% damaged starch.
Effect of milling conditions on damaged starch and reducing sugar content of whole wheat flour
Four different wheat varieties were procured from local market and milled at local flour mill. As the milling conditions were similar, less variation was observed in the damaged starch content among the wheat varieties (Table1), although a correlation between damaged starch content in the flour and the acrylamide content of the chapattis and pooris prepared from them was observed.
Further, we procured lokwan wheat cultivar, and prepared flours with damaged starch content in the range of 6 to 28 % by altering the milling conditions such as moisture (9.4, 14.7 and 20%), aperture (2, 3 and 4 mm), and feed rate (0.21, 0.63 and 1.05 min per 200g) using laboratory scale milling.
An increase in damaged starch content in the wheat flour also showed an increase in the content of reducing sugars (Fig 1).
Human diet is a complex mix of compounds that provides us with energy and important nutrients. Some compounds are beneficial, while others may be harmful. One such compound formed during food processing is acrylamide, whose toxicological effects are well known.
Genetic damage in animals and cultured animal cells due to binding of DNA with glycidamide (a metabolite of acrylamide), skin and lung cancer in mice.
Classification of acrylamide as ‘probably carcinogenic to man’ by The International Agency on Research of Cancer (IARC) (Group 2A; IARC, 1994), adverse effects on neurological and reproductive effects (EC, 2000), and presence of acrylamide-hemoglobin adducts in blood of rats fed standard fried feed are some of the manifestations of acrylamide.
High levels of acrylamide in commercially available heat-treated carbohydrate-rich foods are well reported .
The shorter sugar chain formed more acrylamide, which is in accordance with the Maillard reaction.
Substantial variation that has been found in acrylamide concentration in wheat based foods cannot wholly be explained on the basis of processing conditions.
Reducing sugar content in wheat flour increases during milling, which could affect acrylamide formation by reacting with asparagine. This route is thought to be a major route for acrylamide formation in starchy foods.
Added component
Concentration (µmol/g flour)
pH dough
Acrylamide (g/kg)
Acrylamide reduction (%)a
Sensory scoreb
Control
5.60±0.01
130.55±2.50 9
Citric acid 10
4.87±0.02
60.50±5.50 54 8 50
4.51±0.02
6.92±3.04 95 5
100
3.92±0.01
4.00±1.98 97 3
Glycine
5.64±0.01
95.86±5.60 26
5.61±0.02
82.63±4.42 37 7
L-Lysine
5.63±0.02
76.59±1.90 41
5.60±0.02
60.55±4.80
L-Cysteine
5.65±0.01
24.49±2.14 81
Calcium chloride
6.26±0.03
40.29±3.24 69
6.06±0.02
36.19±8.47 72
Calcium-L-lactate
6.02±0.01
73.99±1.12 43
6.00±0.01
66.36±1.58 49
Vitamin B7 (biotin)
0.5c
5.67±0.02
70.27±4.70 45
Vitamin B1 (thiamine)
5.68±0.01
68.59±1.16 47
Variation in acrylamide content of two Indian traditional products, chapatti and poori was observed with respect to the damaged starch content in whole wheat flour of different wheat varieties from which these products were prepared. Wheat cultivar ‘lokwan’ was milled by altering mill aperture, feed rate and moisture content to obtain whole wheat flour with damaged starch contents ranging from 6.23 to 28.12%. Acrylamide content of the chapatti and pooris prepared from such flours ranged from 12.5 to 65.5 g/kg in chapatti, and 25.5 to g/kg in pooris. Impact of several additives showed 10 µmol/g flour citric acid, and 100 µmol/g flour calcium chloride to reduce acrylamide in pooris by approximately 54 and 72%, respectively, without altering the sensory analysis of the products.
Fig 2. Effect of damaged starch on acrylamide formation in pooris and chapattis
Fig 1. Correlation between damaged starch and reducing sugar content of whole wheat flour
MATERIALS AND METHODS
Optimization of moisture content (%) in whole wheat
Optimization of feed rate (g/min)
Effect of damaged starch on acrylamide content of chapattis and pooris
The whole wheat flour with varying damaged starch was further processed to make chapattis and pooris, which were analysed for their acrylamide content (Fig2).
Acrylamide content in both products increased with an increase in the damaged starch content of the whole wheat flour.
Wheat flour having lowest damaged starch content of 6.23% showed acrylamide content of 12.5±1.50 and 25.5±2.53 g/l in chapattis and pooris, respectively. Similarly, whole wheat flour with highest damaged starch of 28.12% showed a maximum acrylamide content of 65.5±2.30 and ±2.50 g/kg in chapattis and pooris, respectively.
It should be noted that in all cases, the deep-fat fried pooris had higher acrylamide content than chapattis baked on a hot pan.
Lokwan wheat cultivar
Acrylamide content
Damaged starch content
Reducing sugar content
Sensory analysis
Optimization of aperture (mm)
RESULTS AND DISCUSSION
aCompared to poori made with addition of water (control).
bMean of 10 values rounded to whole number.
cAdded at 0.5% of whole wheat flour.
Table1. Acrylamide content of chapattis and pooris prepared by using locally available wheat varieties
CONCLUSIONS
S.No
Wheat varieties
Damaged starch (%)
Acrylamide (g/kg)
Chapatti
Poori 1.
MP Cross S.H.R
30±0.05
58.6±1.5a
228.0±1.8e 2.
MP lokwan
27±0.04
47.2±2.2b
114.0±4.2f 3.
Lokwan
26±0.05
45.8±0.8c
85.9±1.5g 4.
MP sharbati
29±0.03
52.5±2.5d
175.5±9.0h
Effect of additives on pH, acrylamide formation and sensory score of pooris
Citric acid at 50 and 100 µmol/g of whole wheat flour could reduce the acrylamide content totally, the pooris had a very sour taste and were totally unacceptable. Lowering the citric acid concentration to 10 µmol/g of whole wheat flour gave an acceptable product, but could reduce the acrylamide content only by 54 %.
A 69 and 72 % reduction in acrylamide was observed on addition of calcium chloride at 50 and 100 µmol/g of whole wheat flour, respectively. This addition did not alter the sensory profile significantly.
Both these vitamins at 0.5 % (based on the wheat flour) reduced acrylamide by 45-47%.
This was not evaluated further owing to the unfavorable economics of using these vitamins, and the fact other compounds such as calcium chloride was a better and economical choice to mitigate acrylamide content in pooris.
CONTACT
Reducing sugar of whole wheat flour increased with an increase in damaged starch content of whole wheat flour. Damaged starch content showed a strong positive correlation with acrylamide formation in chapattis as well as in pooris. Chapattis had lower acrylamide content than pooris in all cases. Among the various compounds screened for reducing the acrylamide content in pooris, calcium chloride at 100µmol/g flour was the most effective. It reduced the acrylamide content by 72 % without any adverse effect on the sensory properties.
Mehraj Fatema