Chemical composition
of some ready-to-eat
meals consumed in
Qatar
J.H. Al-Jedah and
R.K. Robinson
Introduction
Fish, meat or lentils are the common
ingredients of many traditional meals in Qatar and the other countries around the Arabian Gulf (Al Nagdyet al., 1994; Musaigeret al., 1998), and few would criticise the nutritional value of these basic components. However, as women have begun to find full-time
employment in industry and commerce and spend many hours outside the house, so family meal times have had to be sacrificed. As a consequence, young people are eating many more snack meals like sandwiches, pizzas and burgers, and with the inevitable questions about possible declines in nutrient intake.
Obviously there have been a number of surveys carried out in Europe and North America to establish that ``fast food'' need not be inappropriate from a nutritional
standpoint (Farrer, 1990; MAFF, 1995), but many parents remain concerned when they hear on the media the phrase ``fast food'' being equated with ``junk food''. Clearly generalisations about the impact of changes in eating habits are largely meaningless, because so much depends upon the frequency with which filled rolls or pizzas replace a more traditional meal. Nevertheless, the concern persists and, in order to provide ``local'' consumers with some factual information, it was decided to evaluate the impact on a young, adult male of replacing a traditional dinner cooked at home with a ready-to-eat meal obtained from a typical ``fast-food'' outlet.
More specifically, the aim of the project was to:
(1) purchase a range of ready-to-eat meals from ``take-away'' restaurants in Doha; and
(2) analyse them for levels of major nutrients, in order to see how, at least in gross nutritional terms, such meals might contribute to a typical daily requirement for nutrients.
Materials and methods
Typical portions of pizzas, sandwiches and filled rolls were purchased from take-away restaurants located around the centre of Doha, and each ``meal'' was held in a
The authors
J.H. Al-Jedahis based at the Food Control Laboratory, Doha, Qatar.
R.K. Robinsonis based in the Department of Food Science and Technology, University of Reading, Reading, UK.
Keywords
Fast food, Chemicals, Diet, Qatar
Abstract
Ready-to-eat meals, such as pizzas and filled rolls, purchased from ``take-away'' outlets in Qatar were found to contain sufficient protein in the form of meat, fish or cheese to supply approximately 50 per cent of the recommended daily intake (RDI) for a young adult male. Sufficient energy to utilise this protein was provided in the form of associated fat or carbohydrates. The same foods also make a contribution to the daily requirements for minerals like zinc and iron but, while the calcium content of pizzas was reasonably consistent (approximately 50 per cent RDI), the filled rolls were much more variable. Potassium was identified as a major deficiency along with, to a lesser extent, magnesium, and even the best pizza provided only approximately 20 per cent of recommended intake of dietary fibre.
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Nutrition & Food Science
cool-box at around 48C for transport to the laboratory.
The major components of each consumer portion were weighed individually, and the entire meal was then macerated in a high-speed blender (Moulinex, Paris, France). Duplicate sub-samples (100g) of the
macerate were extracted from the blender for analysis for moisture, crude protein, fat and ash. The moisture content of each sub-sample was determined according to ADAS (1986), as was the ash content. The fat content was measured by extraction with petroleum spirit in a Soxtec extractor (Kirk and Sawyer, 1991), and total nitrogen content of the sample was found by the Dumas method using a Leco Nitrogen Determinator (Leco Instruments Ltd, Stockport, UK); the protein content was calculated as total nitrogen multiplied by 6.25 (Kirk and Sawyer, 1991). The fibre was estimated by the procedure of AOAC (1990), and total carbohydrates were estimated by difference. The energy value was calculated using the formula suggested by Kirk and Sawyer (1991).
Analysis of minerals
The ash was digested in 5ml of 2N HNO3
(Analar Grade) by boiling for about two minutes and then cooling to room
temperature. The cooled solution was filtered through Whatman filter paper (No. 41) and made up to 25ml with 2N nitric acid; a ``blank'' was prepared in a similar manner. The samples were then analysed for lead, iron, copper, zinc, calcium, magnesium and potassium by atomic absorption (AOAC, 1990)
Results and discussion
The weights of the different components of the ready-to-eat meals are shown in Table I and, while the bases of the pizzas were fairly uniform in weight, the toppings varied by nearly 30g. This variability was even more noticeable with the filled rolls, with total weights ranging from 150-295g; perhaps more relevant was the fact that it was the nutritionally important elements like salad materials that were missing. Chicken and French fries should clearly provide, perhaps not unexpectedly, a satisfying meal, but the sandwiches would do little more than provide a temporary respite from the ``pangs'' of hunger.
This crude analysis is supported by the compositional data in Table II. Thus in comparison with the dietary reference values shown, it is evident that the pizzas and many of the filled rolls provide adequate levels of both carbohydrates and fats. The total fat content of one of the filled rolls (1) appeared somewhat excessive, the more so as most of the fat is likely to be saturated; by contrast, the fat in pizzas should, if made to traditional recipes, be olive oil. Nevertheless, the fat and carbohydrate together would make a useful input to the energy requirements of a typical young adult, and in many cases it exceeded 50 per cent of the daily demand.
The contributions of fibre to the diet made by pizzas or filled rolls were, in some cases, negligible, but it is of note that, by contrast, the protein contents of the meals could provide nearly 50 per cent of a daily requirement. As much of the protein was derived from meat, fish or cheese, the amino acid spectrum and digestibility of the proteins are likely to be good. The more extensive meal of chicken and ``chips'' provided over 50 per cent of the daily protein requirements and around 40 per cent of the total energy needs, but the sandwiches were, by contrast, in line with their anticipated dietary role as a ``snack''. Indeed, it would take around ten sandwiches to meet the suggested energy intake for a young adult, and the
accompanying intake of approximately 120g of saturated fat might be open to criticism.
Assuming that the minerals like iron, copper and zinc are ``bio-available'', some of the filled rolls were able to provide the entire daily intake for a young male adult of one or more of these minerals (see Table III), while rolls (1) and (2) met 50 per cent of the requirement for calcium. The differences between the rolls with respect to calcium could be a reflection on the different types of flour being used, because many countries still require certain flours to be fortified with calcium (Kirk and Sawyer, 1991). In some types of filled rolls, analogue cheeses provide good sources of minerals, but the nature of the cheese in roll (1) is not known. If a sweet dessert like yogurt (Tamime and Robinson, 1999) or dates (Ahmedet al., 1995) were to be taken after one of the ready-to-eat meals, then intakes of calcium or potassium would increase, respectively. Dates are also an excellent source of non-absorbable carbohydrates, so that the consumption of this
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Chemical composition of some ready-to-eat meals consumed in Qatar J.H. Al-Jedah and R.K. Robinson
Table IThe range of ready-to-eat meals sampled during the survey
Pizzas (1) with base (148g) and meat, vegetables and cheese (98g) Total weight of food consumed = 246g
(2) with base (156g) and vegetables and cheese (87g) Total weight of food consumed = 243g
(3) with base (154g) and shrimps, vegetables and cheese (107g) Total weight of food consumed = 261g
(4) with base (158g) and chicken, vegetables and cheese (114g) Total weight of food consumed = 272g
Sandwiches (1) with white bread (39g), meat (64g) and salad/grated cheese (19g) Total weight of food consumed = 122g
(2) with taco bread (23g), minced beef (56g) and salad/grated cheese (10g) Total weight of food consumed = 89g
(3) with white bread (39g), chicken (42g) and salad/grated cheese (19g) Total weight of food consumed = 100g
Filled rolls (1) with white roll (135g), meat (69g) and salad/grated cheese (91g) Total weight of food consumed = 295g
(2) with white roll (120g), roast beef (81g) and salad (50g) Total weight of food consumed = 251g
(3) with white roll (80g), roast beef (63g) and salad (17g) Total weight of food consumed = 160g
(4) with white roll (127g), roast chicken (80g) and salad (39g) Total weight of food consumed = 246g
(5) with white roll (67g), grilled fish (86g) and salad (4g) Total weight of food consumed = 157g
Fried chicken and French fries (1) with chicken (131g) and French fries (144g) Total weight of food consumed = 275g
Table IIProximate composition of some widely consumed snack foods bought from restaurants in Doha, Qatar
Meals
Moisture (g)
Fat (g)
Protein (g)
Ash (g)
Carbohydrates (g)
Fibre (g)
Energy (Kcal)
Pizza (1)a 120.8 23.4 25.8 5.2 68.4 2.7 1,403.7
Pizza (2)a 137.3 11.9 22.4 4.1 63.7 3.8 1,055.6
Pizza (3)a 148.2 15.1 27.6 4.2 62.9 2.6 1,260.9
Pizza (4)a 159.6 15.2 32.0 4.9 56.8 3.0 1,304.0
Sandwich (1)a 60.6 12.8 14.9 2.8 29.8 1.0 350.1
Sandwich (2)a 42.1 13.5 14.0 2.3 16.2 0.9 213.1
Sandwich (3)a 46.2 10.7 20.2 2.5 19.7 0.7 252.2
Filled roll (1)a 160.5 42.5 27.7 4.4 58.1 1.8 2,099.8
Filled roll (2)a 141.3 25.6 25.9 4.3 52.5 1.5 1,330.3
Filled roll (3)a 78.6 13.8 27.4 3.0 35.8 1.3 590.2
Filled roll (4)a 135.1 25.3 23.6 3.7 54.9 2.0 1,311.7
Filled roll (5)a 72.0 17.4 21.6 4.1 33.6 1.4 579.0
Fried chicken (1)a 60.8 30.3 24.1 2.4 13.0 0.4 546.8
French friesa 64.1 18.3 4.8 3.7 51.4 1.7 540.1
Reference nutrient intakes (per day) for men (20+)b
33.0 55.5 na 47.0 18.0 2,550.0
Notes:All figures as g per total weight of edible material (calculated energy as Kcal). Reference intakes quoted as g per day and energy as Kcal per day
Sources:aHollandet al. (1991).bHMSO (1991)
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Chemical composition of some ready-to-eat meals consumed in Qatar J.H. Al-Jedah and R.K. Robinson
traditional fruit of the Arabian deserts has much to recommend it.
What emerges from these data is that the light meals available in Doha can make a useful contribution to the daily nutrient requirements of the generation most likely to consume them. Clearly elements like protein and fibre are deficient compared to some traditional meals at home (Musaigeret al., 1998), and minerals like magnesium and potassium fall well short of dietary ``norms''. The lower energy intake provided by many traditional meals could be important as well, for Madani (1995) found that, in 1974/1975 before Western foods had a major impact, the average energy intake in Saudi Arabia was only 1,807Kcals/day. Nowadays, average energy intake has risen to over 3,000Kcals/day, with many of the calories derived from a high intake of animal fat.
Nevertheless, the data recorded in Qatar suggest that a balanced intake of traditional and ready-to-eat meals will provide the younger generation with ``fun and variety'', and without too great a risk of affluence-related diseases like obesity.
References
ADAS (1986),The Analysis of Agricultural Materials: A Manual of the Analytical Methods used by the Agricultural Development and Advisory Service,
3rd ed., Ministry of Agriculture, Fisheries and Food, London.
Ahmed, I.A., Ahmed, A.K. and Robinson, R.K. (1995), ``Chemical composition of date varieties as influenced by the stage of ripening'',Food Chemistry, Vol. 54, pp. 305-9.
Al-Nagdy, S.A., Abd-El Ghani, S.A. and Abdel-Rahman, M.O. (1994), ``Chemical assessment of some traditional Qatari dishes'',Food Chemistry, Vol. 49, pp. 261-4.
AOAC (1990),Official Methods of Analysis, Volume 1, 15th ed., AOAC, Arlington.
Farrer, K.T.H. (1990), ``Nutritional implications'', in Booth, R.G. (Ed.),Snack Food, Van Nostrand Reinhold, New York, NY.
HMSO (1991),Dietary Reference Values for Food Energy and Nutrients for the United Kingdom, Report No. 41, Department of Health, London.
Holland, B., Welch, A.A., Unwin, I.D., Buss, D.H., Paul, A.A. and Southgate, D.A.T. (1991),McCance and Widdowson's The Composition of Foods, Royal Society of Chemistry, London.
Kirk, R.S. and Sawyer, R. (1991),Pearson's Chemical Analysis of Foods, Churchill Livingstone, London. Madani, K.A. (1995), ``Food consumption patterns in Saudi
Arabia'', in Musaiger, A.O. and Miladi, S.S. (Eds), Food Consumption Patterns and Dietary Habits in the Arab Countries of the Gulf, FAO Regional Office, Cairo.
MAFF (1995),Nutrient Analysis of Pizzas. Food Surveillance Report, MAFF Library, London. Musaiger, A.O., Ahmed, M.A. and Roa, M.V. (1998),
``Chemical composition of some traditional dishes of Oman'',Food Chemistry, Vol. 61, pp. 17-22. Tamime, A.Y. and Robinson, R.K. (1999),Yoghurt ±
Science and Technology, Woodhead Publishers Ltd, Cambridge.
Table IIIMineral contents of some some widely consumed snack foods bought from restaurants in Doha, Qatar
Meals
Pizza (1)a 3.84 0.54 4.58 251.78 98.00 796.99
Pizza (2)a 3.98 0.70 3.96 425.98 94.84 935.28
Pizza (3)a 4.64 0.78 3.73 317.50 105.97 812.52
Pizza (4)a 4.32 0.76 4.68 393.56 121.01 1,267.00
Sandwich (1)a 1.90 0.33 1.25 86.91 51.88 443.43
Sandwich (2)a 2.83 0.14 4.19 375.58 56.42 382.07
Sandwich (3)a 2.19 0.14 1.94 391.20 43.99 380.50
Filled roll (1)a 4.93 0.62 9.03 385.36 117.85 1,180.86
Filled roll (2)a 12.95 1.85 9.19 161.94 114.91 1,221.47
Filled roll (3)a 3.62 0.50 5.04 118.72 79.82 918.10
Filled roll (4)a 10.60 0.71 2.61 252.15 121.50 1,058.60
Filled roll (5)a 4.77 0.14 4.55 411.12 67.99 584.42
Fried chicken (1)a 6.01 0.52 2.03 49.31 61.19 704.54
French friesa 2.30 0.32 0.24 50.18 74.69 1,822.97
Reference nutrient intakes (per day) for men (20+)b
8.7 1.2 9.5 700 300 3,500.0
Notes:All figures as mg per total weight of edible material (calculated energy as Kcal). Reference intakes quoted as mg per day and energy as Kcal per day
Sources:aHollandet al. (1991).bHMSO (1991)
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