Nutrients, bioactive non-nutrients and anti-nutrients in potatoes

Globally, potatoes account for only about 2% of the food energy supply, yet they are the predominant staple for many countries. In developed countries, potatoes account for 540 kJ (130 kcal) per person per day, while in developing countries, it is only 170 kJ (42 kcal) per person per day. In addition to energy, which is derived almost entirely from their carbohydrate content, many varieties of potatoes contribute nutritionally important amounts of dietary fibre (up to 3.3%), ascorbic acid (up to 42 mg/100 g), potassium (up to 693.8 mg/100 g), total carotenoids (up to 2700 mcg/100 g), and antioxidant phenols such as chlorogenic acid (up to 1570 mcg/100 g) and its polymers, and anti-nutrients such as α-solanine (0.001–47.2 mg/100 g); and lesser amounts of protein (0.85–4.2%), amino acids, other minerals and vitamins, and other beneficial and harmful bioactive components. Nutrient content depends on a number of factors, with variety being among the most important. Potato biodiversity is vast, with more than 4000 known varieties. Most belong to the species Solanum tuberosum, but another 10 species are cultivated and 200 wild species have been identified. Modern agricultural practices and climate change are contributing to the loss of potato biodiversity, and thus the loss of the genes coding for nutrient biosynthetic pathways. Knowledge of differences in nutrient composition of potatoes related to their genetic diversity will help guide strategies that may contribute to reducing biodiversity loss and improving food and nutrition security.     

Glycoalkaloids in potatoes: Content of glycoalkaloids in potatoes for consumption

Potatoes contain glycoalkaloids in varying levels depending upon variety, treatment and so on. Glycoalkaloids are potentially toxic at the natural levels in potatoes, and Nordic assessments recommend that the safety levels of total glycoalkaloids (TGA) in new potato varieties should not exceed 100 mg/kg. Thus the aim of this study was to make a survey of the distribution and contents of TGA in potatoes on the Danish market, including many different and relevant varieties during a 6-year period. A total of 386 samples of potato tubers were analysed for α-solanine and α-chaconine by extraction with acetic acid and determination by RP-HPLC with UV-detection at 202 nm. The results not only confirmed that contents above 100 mg TGA/kg in potato tubers frequently occurred in some years, but also showed the possibility of finding lower contents in the same varieties other years. This led to the cautious conclusion that by careful selection of varieties and environmental conditions, generally providing consumers with potatoes containing less than 100 mg TGA/kg would be possible.     

Ascorbic acid concentration of native Andean potato varieties as affected by environment, cooking and storage

The ascorbic acid (AA) concentration of tubers was determined in 25 Andean potato varieties (Solanum tuberosum L.) grown in three environments, and the effect of cooking and storage time in subsets of samples was evaluated. Significant variation due to genotype, environment and genotype × environment (G × E) interaction was found. AA concentration in freshly harvested raw, peeled tubers ranged from 22.2 to 121.4 mg/100 g on a dry weight basis (DW) and from 6.5 to 36.9 mg/100 g on a fresh weight basis (FW) with the accession 704393 showing the highest levels of AA in all three locations. Differences in AA concentration were found among cooking methods and storage times; and significant non-crossover interactions with genotype were observed for both of these parameters. It was found that AA concentration of boiled tubers of the six varieties evaluated was higher than in oven and microwaved tubers and that AA concentration of tubers of the 23 varieties evaluated decreased with storage time. The variety 704393 retained 54 and 34% of its original AA concentration after boiling and storage during 26 weeks under farmer conditions. One hundred grams of fresh harvested boiled potatoes of this variety (704393) could provide adults with 17–20% of the recommended daily allowance (RDA) of AA.     

Variations in the carotenoid and anthocyanin contents of Korean cultural varieties and home-processed sweet potatoes

The sweet potato is an important industrial crop and a source of food that contains useful dietary fiber and vitamins. Recently, orange- and purple-fleshed varieties have come under the spotlight due to their healthful components, carotenoids and anthocyanins, respectively. In this study, an HPLC-DAD method was applied to determine the carotenoid composition and content in nine Korean cultural varieties of sweet potato. Changes in carotenoid contents and composition were also observed during home-processing of an orange-fleshed cultivar with high carotenoid content (530 ± 60 μg/g of dry weight, DW as all-trans-β-carotene). A loss of the carotenoids was observed for all of the home-processing methods examined; the baked or boiled or steamed sweet potatoes had higher amounts of all-trans-β-carotene (246 ± 34, 253 ± 29 and 240 ± 21 μg/g DW, respectively) than pressure-cooked, sautéed and fried ones (194 ± 21, 201 ± 28 and 111 ± 19 μg/g DW, respectively). Interestingly, cis-isomer of the all-trans-β-carotene, 13Z-β-carotene was found in elevated amounts in all of the processed samples, particularly in baked, pressure-cooked and steamed sweet potatoes compared to control. Variations in anthocyanin content in the nine cultural varieties and home-processed sweet potatoes were also determined by an HPLC-DAD method.     

The influence of nitrogen and potassium fertilisation on the content of polyphenolic compounds and antioxidant capacity of coloured potato

The effect of fertilisation rates of nitrogen: 0 (control treatment—no soil fertilisation), 40, 80 and 120 kg/ha and potassium: 0 (control treatment), 120, 150 and 180 kg/ha on the content of anthocyanins, phenolic acids and antioxidant capacity in purple–blue potato cv. ‘Blue Congo’ was examined. Anthocyanins and phenolic acids were identified and quantified by LC–MS and UPLC–PDA. Nitrogen was more effective in increasing the anthocyanin content—their quantity in tubers after nitrogen application was twice as much as that found after potassium application. Among phenolic acids, the dominant one was chlorogenic acid, the content of which significantly increased after nitrogen fertilisation at 120 kg/ha, in line with the increase in total concentration of phenolic acids and antioxidant capacity. The adjustment of nitrogen and potassium fertilisation levels during the growth of purple–blue potatoes seems to be an effective way to increase the expression of polyphenolic compounds in these cultivars. Therefore, fertilisation with N at 120 kg/ha and K at 120 and 150 kg/ha is recommended as a way to improve the content of biologically active compounds and antioxidant properties, and consequently, to enhance the nutritional value and the functionality of purple–blue potatoes.     

The effect of frying on anthocyanin stability and antioxidant activity of crisps from red- and purple-fleshed potatoes (Solanum tuberosum L.)

Red- and purple-fleshed potatoes (Solanum tuberosum L.) are a good source of polyphenols, mainly anthocyanins as one of the most important components. The chemical composition with reducing sugars and the total polyphenol contents were analyzed in four purple potato varieties (Salad Blue, Vitelotte, Valfi, Blue Congo) and three red-fleshed potato varieties (Rosalinde, Herbie 26, Highland Burgundy Red). The anthocyanin composition of raw potato and potato crisps was characterized by high-performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS) method. Moreover, the antioxidant activity was measured with the radical scavenging assays using 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical as well as ferric reducing ability of plasma assay (FRAP). In addition, colour parameters in prepared potato crisps were evaluated. Both red and purple-fleshed potato varieties contained high levels of total polyphenols (227–845 mg 100 g⁻¹ dry weight) and anthocyanins (21–109 mg 100 g⁻¹ dry weight). The process of frying caused degradation of anthocyanin compounds (38–70%). The HPLC–MS/MS analysis showed that pelargonidin and malvidin derivates were more stable during frying than petunidin derivatives. Although frying process affected the anthocyanin and polyphenol levels, obtained potato crisps exhibited bright intensive colour and good antioxidant activity.     

Nutritional composition of freshly harvested and stored Latvian potato (Solanum tuberosum L.) varieties depending on traditional cooking methods

The information about nutritional composition of potatoes at both the ingredient and recipe levels in the Food Composition Data Base (FCDB) of Latvia is insufficient. Therefore, the aim of this research was to determine the nutritional composition and energy content of potatoes prepared by traditional cooking methods before and after storage. Five Latvian potato varieties were selected: Lenora, Brasla, Imanta, Zile and Madara. A two-year research was conducted during two periods: just after harvesting (2007, 2008) and after six months of storage (2008, 2009). The following cooking methods were used: shallow frying (150 ± 5 °C); deep-fat frying (180 ± 5 °C) and roasting (210 ± 5 °C). The weight of the potatoes was recorded before and after frying along with the time and temperature during frying. Chemical analyses were performed to determine the content of reducing sugars, starch, fructose, glucose, sucrose, fibre, fat, protein, moisture, vitamin C and amino acids. The content of the analyzed nutrients differed significantly between both potato varieties and applied cooking methods: differences between potato varieties and cooking methods were found for vitamin C, moisture, reducing sugars, fructose, glucose, sucrose, amino acids, essential amino acids, and energy content, whereas significant differences in starch, fibre, fat and protein content were found between cooking methods.     

Phenolic content and antioxidant capacity of Philippine potato (Solanum tuberosum) tubers

Four potato (Solanum tuberosum) varieties – Bengueta, Ganza, Igorota and 125411.22 – were analyzed for total phenolic content and antioxidant activities to provide baseline data for Philippine potato varieties. Bengueta had the highest phenolic content with 50.0 ± 1.5 mg gallic acid equivalent (GAE)/100 g (dry basis, DB). It also had the highest DPPH radical scavenging activity with an EC₅₀ value of 30.6 ± 3.6 mg/mL (DB). The potato variety125411.22 had the highest reducing power with EC₅₀ equal to 66.2 ± 1.6 mg/mL (DB), while Igorota had the highest iron-chelating capacity with an EC₅₀ of 11.0 ± 3.2 mg/mL (DB) and the best inhibitory action against linoleic acid oxidation at 95.4 ± 2.2% at 50 mg/mL sample concentration. Methanolic potato extracts had better antioxidant activity than α-tocopherol and better iron chelating capacity than ethylenediamine tetraacetic acid (EDTA). Significant (^*P < 0.05) negative correlation (R = −0.542) was observed between total phenolic content and the EC₅₀ values for DPPH radical scavenging activity, but none between total phenolic content and reducing power, iron-chelating capacity and total antioxidant activity.     

Tuber quality and nutritional components of “early” potato subjected to chemical haulm desiccation

“Early” potato is a typical crop grown in most of the Mediterranean countries, and it is one of the most important horticultural crops exported towards the Northern European markets. In order to improve market value of early potatoes, growers are more and more involved in choosing new potato varieties and constantly looking for methods to improve the commercial quality of tubers. One of the most increasingly used agro-techniques is chemical haulm desiccation, which aims to simplify harvesting and can help to manipulate tuber size distribution and tuber skin-set. Its effect on yield and quality aspects of early potato remains to be better evaluated. This paper resumes results of trials and analysis conducted during 2007 concerning the effect of the application of a chemical desiccant (gluphosinate ammonium) on some relevant nutritional parameters of three early potato varieties (Spunta, Ditta, and Krone) grown in Southern Italy. Tubers from the trials were analyzed for tuber size distribution, flesh and skin colour, dry matter, nitrate, soluble carbohydrates, total and resistant starch, vitamin C, phenol content, and total antioxidant activity. Results indicate that chemical desiccation does not affect the levels of vitamin C and those of other molecules with antioxidant properties as well as those of total soluble carbohydrates. On the other hand, it induces a significant decrease in starch storage and an increase in the percentage of resistant starch (a component of dietary fibre).     

Phytonutrient content of Solanum sisymbriifolium Lam. berries

Solanum sisymbriifolium Lam. (Litchi tomato) is grown ornamentally, and in Europe it is used as a trap crop for management of the potato cyst nematode (PCN). Its berries are edible, but little is known about their nutritional content. If more was known about their nutritional value this could provide incentive to grow it as a food crop. Phytonutrient content was characterized in berries from four varieties and four synthetic breeding lines developed to have reduced spininess. Litchi tomatoes contained 6.8–10.4 mg of total phenolics per g dry weight. Antioxidants measured by FRAP ranged from 148 to 242 μmol TE/g DW. HPLC analysis showed chlorogenic acid (1856–4385 μg/g DW) was the most abundant phenylpropanoid. Ascorbic acid ranged from 2042 to 4511 μg/g DW. The yellow/orange flesh color was due to carotenoids, with β-carotene the most abundant (204–633 μg/g DW). Soluble protein in Litchi tomato ranged from 86.9 to 120.9 mg/g. Of the cultivated Litchi tomato varieties analyzed, SS91 had the highest amount of antioxidant activity, ascorbic acid, chlorogenic acid and β-carotene. These results suggest that Litchi tomato fruits can be a good source of phytonutrients, expanding the plant's functionality beyond its use as a PCN trap crop.     

The nutritional value of potatoes and potato products in the UK diet

Total potato consumption has been declining slowly in the UK at a rate of about 1–2% per year, in tandem with an increase in consumption of other starchy staples such as pasta and rice. Consumers and even health professionals often have a negative perception of potatoes and of chips in particular. We have evaluated the nutritional contribution of potatoes and potato products to the British diet by a secondary analysis of four‐day dietary records from the National Diet and Nutrition Survey 2008–2011, and distinguished between consumption of fried chips and oven chips. We also calculated portion sizes of six different types of potato dishes [oven chips, fried chips, boiled potatoes, mashed potatoes, roast potatoes and jacket (baked) potatoes]. Over 92% of respondents consumed potatoes during the four‐day survey, 27% consumed oven chips and 41% consumed fried chips. Potatoes (including chips) contributed 7% of total energy, but greater proportions of potassium and vitamin B₆ (15%), vitamin C (14%), fibre (13%), folate (10%) and magnesium (9%). On the other hand, they contributed only 4% of saturated fatty acids. Per capita consumption of potatoes averaged 85 g/day, of which, fried chips contributed 20 g/day and oven chips 10 g/day. For fried chips, mean portion size per occasion was 149 g among adults, 138 g among teenagers and 94 g among 4‐ to 10‐year‐olds, while portion sizes for oven chips were slightly smaller. Potatoes can increase the nutrient density of the diet by providing a relatively high micronutrient contribution, compared with energy content, while delivering only modest amounts of saturated fatty acid and sodium. Reformulation to remove trans fatty acids and reduce saturated fatty acid and salt has improved the nutritional profile of some potato products. Still, there may be scope in catering establishments to offer smaller portions, thicker chips and more oven‐baked potato products. Nutritionally, potatoes and potato products should be seen as a white vegetable, whose consumption should be encouraged alongside other, coloured, vegetables.     

Understanding the role of potatoes in the Peruvian diet: An approach that combines food composition with household expenditure data

Agricultural research in developing countries has increasingly focused on meeting nutritional objectives. Biofortified varieties and increased use of fertilizers have been studied to improve the nutrient profile of staple foods and thereby reduce micronutrient malnutrition. To understand where and for which crops this is appropriate, a better understanding of population-level consumption patterns is needed. In this paper, we demonstrate an approach to understanding the role of the potato in the Peruvian diet, and how it varies by geographic and socio-economic group. We combine readily available data on household expenditures from a Peruvian living conditions survey (ENAHO) with food composition data to derive estimates on the amount of potatoes consumed per adult equivalent, and the contribution of potatoes to meeting the energy, protein, calcium, iron, and vitamin C needs of Peruvians. Households in the highlands, where potatoes are often the basis of cropping systems, consume the greatest quantities of potatoes, averaging 421 g/adult equivalent/day (g/ae/d). In this region, potatoes contribute 18%, 16%, 17%, and 97% of the recommended needs for energy, protein, iron, and vitamin C, respectively. Sensitivity testing using different cultivars previously examined from the Peruvian highlands shows that potatoes could supply a range from 7–31% of the recommended intakes for iron in this population. This work gives support for continuing agricultural research to reduce micronutrient malnutrition and provides guidance for where and with whom such research might have the greatest impact.     

Diversity in composition of scarlet (S. aethiopicum) and gboma (S. macrocarpon) eggplants and of interspecific hybrids between S. aethiopicum and common eggplant (S. melongena)

Scarlet (Solanum aethiopicum) and gboma (S. macrocarpon) eggplants are cultivated vegetable crops native to Africa, for which no comprehensive reports exist on composition and diversity. We have evaluated diversity in composition of three varieties of scarlet eggplant and four varieties of gboma eggplant, as well as of four interspecific hybrids between scarlet and common eggplant (S. melongena) and their respective parents. With the exception of moisture (between 85.8 and 88.3 g/100 g) and pH (between 5.32 and 5.89), there was a wide diversity among varieties within each of the species for the composition traits evaluated, revealing ample possibilities for selection of varieties with improved fruit composition. Scarlet eggplant varieties evaluated presented, on average, lower content than gboma eggplant varieties for carbohydrates (3.60 vs 6.48 g/100 g), starch (3.18 vs 6.15 g/100 g), vitamin C (11.6 vs 18.9 mg/100 g), and total phenolics (24.4 vs 144 mg/100 g) and higher values for soluble sugars content and for the ascorbic/dehydroascorbic acid ratio. Interspecific hybrids between scarlet and gboma eggplants presented moisture content (79.0 g/100 g) and pH (5.15) values below those of any of the parents. For the rest of traits, values were intermediate between both parents, although much more similar to the scarlet eggplant parent.     

Protein, iron, zinc and calcium concentrations of potatoes following traditional processing as “chuño”

Samples from unprocessed and processed cooked tubers of the nine most abundant potato cultivars used to prepare the traditional freeze-dried food product, “chuño” in the central highlands of Peru were prepared and analyzed for their protein and mineral concentrations. The protein, iron, zinc and calcium concentration of cooked chuño of the nine cultivars evaluated ranged from 0.49 to 1.15 g, from 0.29 to 0.65 mg, from 0.04 to 0.14 mg and from 18.9 to 31.0 mg per 100 g on a fresh weight basis, respectively. Potatoes processed as chuño have a lower concentration of protein and zinc than unprocessed tubers, and a higher content of calcium, while iron concentration may be expected not to be subjected to changes. Water used in preparing the chuño is suggested to be the cause for an increased calcium concentration in the final product, as the water used had higher calcium content before (1.35 mequiv./l) than after (0.84 mequiv./l) use in the preparation. Thus, water seems to be source of the increased calcium concentration.     

Nutritive value,antioxidant activity and phenolic compounds profile of brewer’s spent yeast extract

Spent yeast is the second major by-product from brewing. Mechanical disruption of yeast cell wall can be used to obtain β-glucan rich ingredients and separate inner yeast content, both with potential applications as food and nutraceutical ingredients. In this work, the nutritional composition, including minerals and B-complex vitamins, together with the antioxidant activity and phenolic compounds profile of yeast extract, prepared by mechanic disruption of brewer’s spent yeast and removal of yeast cell wall, was investigated. The lyophilised yeast extract presented 64% of proteins with high proportion of essential amino acids and 4% of RNA; macrominerals (Na, K, Ca, Mg), trace elements such as Zn (11.9 mg/100 g dw), Fe (1.76 mg/100 g dw), and Mn (0.564 mg/100 g dw), and vitamins B3 (77.2 mg/100 mg dw), B6 (55.1 mg/100 g dw) and B9 (3.01 mg/100 g dw). Two phenolic compounds were quantified as free forms, gallic acid and (±) catechin, whereas other bounded phenolic compounds were also quantified. The nutrients content, antioxidant properties and phenolic composition of the lyophilised brewer’s spent yeast extract indicates that it can be an interesting food or nutraceutical ingredient. Thus, its recovery will be beneficial in terms of sustainability and environmental impact.     

Effect of Storage on Organoleptic Characteristics and Nutritional Evaluation of β -Carotene and Iron-Rich Products

Vitamin A deficiency and iron deficiency anaemia are two major micronutritional disorders of national importance affecting the vulnerable groups of the population. In the present study an effort has been made to combat this problem by developing β -carotene and iron-rich products, namely biscuits and shakarpara by adding cauliflower leaves powder and these were stored to see the effect of storage on their organoleptic and nutritional evaluation. Fresh biscuits and shakarpara were found organoleptically acceptable, whereas the mean scores of organoleptic characteristics decreased gradually after 60 days of storage. Moisture, protein, fat, crude fibre, minerals, carbohydrates and energy contents were 2.98 g, 8.49 g, 20.90 g, 0.90 g, 1.38 g, 65.35 g and 2025 kJ/100 g in biscuits and 6.22 g, 5.38 g, 23.80 g, 0.42 g, 1.08 g, 63.10 g and 2042 kJ/100 g in shakarpara, on fresh weight basis, respectively. β -Carotene content was 1.42 mg/100 g in biscuits and 1.55 mg/100 g in shakarpara, which decreased significantly after 60 days of storage. Total iron content was 7.16 mg/100 g in biscuits and 8.44 mg/100 g in shakarpara. Soluble iron, ionizable iron andin vitro iron at pH 7.50 in biscuits were 2.84 mg/100 g, 1.25 mg/100 g and 8.70% of total iron and inshakarpara 9.96 mg/100g, 1.75 mg/100 g and 10.24% of total iron, respectively, which decreased significantly after 60 days of storage in both products. These products can be stored for up to 30 days without any significant change in organoleptic and nutritional characteristics.     

Analysis of protein amino acids,non-protein amino acids and metabolites,dietary protein,glucose, fructose,sucrose, phenolic,and flavonoid content and antioxidative properties of potato tubers,peels, and cortexes (pulps)

The composition and antioxidative activity of whole potato tubers from five Korean cultivars, three peels from one cultivar, and eight pulps (cortexes) after peeling from six different cultivars were evaluated. Whole tubers were sectioned into three parts followed by analysis of the peels and pulps of each part. The following characteristics were determined: the dimensions and water content of whole tubers; nutritional protein content consisting of protein and free amino acids by an automated Kjeldahl nitrogen assay; free non-protein amino acids, metabolites, and fructose, glucose, and sucrose content by HPLC; phenolic compounds by HPLC and LC/MS; total phenolics and flavonoids by colorimetry; and antioxidative properties by ABTS, DPPH, and FRAP assays. The results demonstrate differences and similarities in the content of nutritional and bioactive compounds and in their bioactivities from whole potatoes, peels, and pulps. The present study reports for the first time the analysis of multiple potato nutrients and bioactive components as well the antioxidative properties of whole potatoes, peels, and pulps derived from the same tubers. The described methods are expected to facilitate the analysis of commercial and newly-developed potato cultivars, peels, and pulps and relate their composition and antioxidative activities to their reported nutritional, health-promoting, and industrial properties.     

Impact of flour particle size on nutrient and phenolic acid composition of commercial wheat varieties

In the present study, the effect of particle size (PS) on phenolic acid content and proximate composition (moisture, ash, protein, total fat, crude fiber and total carbohydrates) of whole-wheat flour (WWF) was determined. Five different particle size fractions <1.18 to>0.43, <0.43 to>0.30, <0.30 to>0.15, < 0.15 to>0.08 mm, and < 0.08 mm (ASTM recommended), of three commercial wheat varieties (Benazir, TJ-83, Imdad) were used for the present study. Total phenolic acid was determined using HPLC-DAD detections after base hydrolysis of the samples. Proximate composition of each particle size fraction of all three wheat flours were determined by recommended AOAC methods. In all wheat varieties, maximum quantities of total phenolic acids (162.12–554.16 mg/100 g) were obtained from <1.18 to>0.43 mm PS fractions. The maximum moisture content (8.12–8.98 g/100 g) was observed in the two lower PS (<0.15 mm) fractions while ash and protein were highest in the largest PS (<1.18 to>0.43) i.e. 2.10–2.77 mg/100 g and 10.9–11.8 mg/100 g respectively. The total fat (0.24-0.53 mg/100 g) and crude fiber (0.40-0.59 mg/100 g) were highest in <0.43 to>0.30 PS fraction of all wheat varieties. The average carbohydrates (g/100 g) and energy (kilojoules) were ranged from 77.4-79.9, 1502.0-–1518.8 for Imdad; 79.7-84.3, 1518.8-–1527.2 for Benazir; and 78.4-81.1, 1506.2-–1518.8 for TJ-83 wheat varieties. Pearson correlation showed negative correlation between particle size and carbohydrate and energy content and positive correlation with phenolic acids content. This study concludes that particle size has direct influence on the distribution of phenolic acids, carbohydrate, protein, crude fiber, ash, crude fat and moisture in the three wheat varieties.     

Nutritional Profile of Local and Western Fast Foods Consumed in Bahrain

The aim of this study was to determine the proximate, mineral, and vitamin content of 16 commonly consumed fast foods (local and Western-based) in Bahrain. Samples were collected from several food outlets in Manama city, the capital of Bahrain, and analyzed using standard methods. In general, the findings revealed that local fast foods had higher cholesterol and energy content (ranging from 0–118 mg and 762–1796 kJ/100 g, respectively) compared to Western fast foods (ranging from 11–34 mg/100 g and 980–1172 kJ/100 g, respectively). Protein content was higher in most of the local fast foods compared to the Western fast foods (5.8–30.4 g/100 g and 10.3–17.9 g/100 g, respectively). Most of the minerals were higher in local fast foods, but calcium (16–153 mg/100 g) and phosphorous (54–273 mg/100 g) were higher in Western fast foods. Some of these foods had considerable levels of vitamin B₆ (0.03–0.25 mg/100 g), vitamin B₁₂ (0.1–2.3 μg/100 g), folacin (9.0–106 μg/100 g), and niacin (1.0–12.1 mg/100 g), while the rest of the vitamins were present to a lesser extent. Fat, energy, and sodium levels were also higher in local fast foods. It is evident that the conception that local fast foods are healthier than Western-based fast foods is inappropriate. Hence, nutrition education programmes need to focus on the nutritional aspects of both local and Western fast foods.     

Phenolic acids in potatoes,vegetables, and some of their products

The aim of this study was to determine the distribution and contents of soluble and total phenolic acids in a wide range of vegetables consumed in Finland. The determinations were performed from the pooled samples (14 potato and 45 other vegetable samples). Soluble phenolic acids were extracted with methanolic acetic acid and a tentative quantification was performed by HPLC. The contents of total phenolic acids were determined by HPLC after alkaline and acid hydrolyses. Chlorogenic acid derivatives were the most dominant soluble phenolic acids, while caffeic acid was the most dominant phenolic acid aglycone in the samples studied. Highest contents of soluble phenolic acids were found in raw and cooked potato peels: 23–45 mg/100 g fresh weight calculated as aglycones. In addition, pot-grown lettuces, Chinese cabbage, broccoli, carrot, aubergine, Jerusalem artichoke, peanut and most of the boiled and peeled potato tubers contained more than 5 mg/100 g of soluble phenolic acids calculated as aglycones. Among the best vegetable sources of total phenolic acids were potatoes, with contents varying from 7.9 mg/100 g (cooked and peeled Rosamunda variety) to 52 mg/100 g (cooked peel of Van Gogh variety), and red cabbage, carrot, aubergine, Jerusalem artichoke, broccoli, pot-grown lettuce, spinach, radish and red beet, with contents from 11 mg/100 g (spinach) to 52 mg/100 g (pot-grown lettuce Lollo Rosso). Variation in the phenolic acid contents of the vegetables was either moderate or considerable and needs further research.