Cooking dependent loss of metabolites in potato breeding lines and their wild and landrace relatives

Elucidating and improving the nutritional value of staple crops is an important focus in breeding programs. Hence, wild and cultivated potatoes have been metabolite profiled to assess metabolic plasticity present in potato tubers and changes that occur in these after cooking. The present data highlighted metabolic similarities of certain wild species to breeding lines, indicating preference during domestication. In the case of potato, the cooking process has to be taken into consideration for the assessment of nutritional quality. The degree of nutritional change during cooking depends on several factors including cooking method, stability of metabolites with nutritional properties and chemotype of the varietal matrix. The differences between raw and boiled tubers were similar within each germplasm group. No notable distinctions of total phenolic levels could be observed within germplasm groups, whereas total carotenoids and glycoalkaloids were significantly decreased. Genotypes/cultivars with notable changes upon cooking distinguished them within their genotype group.     

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.     

Determination of free amino acids in five commercial sweetpotato cultivars by hydrophilic interaction liquid chromatography-mass spectrometry

A sensitive and rapid method was developed for the determination of free amino acid profiles in sweetpotatoes. The method utilized an ultra-high-performance liquid chromatography system with hydrophilic interaction liquid chromatography (HILIC) separation coupled with tandem mass-spectrometry (MS/MS) detection without the need for chemical derivatization. Separation of 36 amino acid standards was achieved on a silica HILIC column in a single MS/MS run of 19 min. This validated method was applied for the analysis of the free amino acid composition of five commercial sweetpotato cultivars (Covington, Beauregard, Hatteras, Murasaki-29 and O’ Henry) from two planting lots grown in experimental fields. Analysis of variance with Tukey’s test was used to determine the differences in individual free amino acid content among the analyzed samples, and principle component analysis (PCA) was implemented to evaluate the variation in amino acid profiles of different sweetpotato cultivars. Asparagine was the most abundant free amino acid and its content varied significantly among the cultivars (p < 0.05). Fifteen additional amino acids also varied among cultivars and contributed to the differentiation of the genotypes by PCA based on their complete amino acid profiles. The efficient, reliable, sensitive method described herein could be used in quantifying amino acids in food matrices similar to sweetpotatoes.     

Chemometric analysis on free amino acids and proximate compositional data for selecting cowpea (Vigna unguiculata L.) diversity

Biodiversity of cowpea, along with the interesting agricultural and nutritional properties, has encouraged research with local landraces of Portugal. This work deals with the composition of dry beans of cowpea from 28 different Portuguese cultivars concerning dry matter (DM), crude proteins (CP), fat content (FC), ash, and concentration of free essential and non-essential amino acids. Data obtained on these traits showed contents of DM, FC, ash, and CP in the ranges of 95.7–98.9%, 1.0–1.6%, 2.7–4.7%, and 18.6–26.9%, respectively. The content in free amino acids was evaluated as an indicator of germinating potential of the diverse cultivars assessed. The amino acids content was the highest in the varieties ‘Vg50’ and ‘Vg58’. Cluster and principal component analyses of the data allowed the identification of the most promising Portuguese landraces of cowpea to be used for breeding new varieties with improved germination potential and nutritional traits.     

Physicochemical properties and proximate composition of tamarillo (Solanum betaceum Cav.) fruits from New Zealand

This study reports physical parameters, proximate compositions, reducing sugar and amino acid contents in Amber, Laird’s Large and Mulligan tamarillos that were produced in New Zealand. Across all three cultivars, about 3 % of dietary fibre was present. Higher amounts of neutral side chains were observed in pectin from Laird’s Large compared to other cultivars and in pectin from pulps compared to peels. Among 22 detected amino acids, 2 essential amino acids and 5 non-essential amino acids were reported herein for the first time. The total amino acids content in peel and pulp of tamarillos ranged from 1192 to 1753 and 3455–6077 mg 100 g⁻¹ dry weight, respectively. l-glutamic acid, γ-aminobutyric acid and l-aspartic acid dominated amino acid profile of tamarillo except for Amber peel. l-histidine and l-lysine dominated the essential amino acid profile of all tamarillo samples. Principal component analysis revealed a clear separation among soluble sugar and amino acid profiles of different cultivars and tissues of tamarillo.     

Amino acid composition and nutritional value of four cultivated South American potato species

Protein content, amino acid composition, nutritional quality and patatin characteristics were determined in tubers of four South American cultivated potato species (Solanum andigenum, Solanum goniocalyx, Solanum phureja, Solanum stenotomum) and a cultivar of the commonly cultivated cultivar Desirée of Solanum tuberosum. Protein content (on dry matter basis) of S. andigenum and S. stenotomum was highest at 7.9% and 8.0%, respectively, and the relative quantities of patatin for both species were 41.7% and 34.0%, respectively. The nutritional value of patatin, in terms of essential amino acid index with respect to a reference protein of FAO/WHO (EAAI_adult) ranged from 93.0% (S. phureja) to 112.5% (S. goniocalyx). In case S. goniocalyx, the patatin fraction was a nutritionally better protein fraction than a protein concentrate or tuber dry matter, which had EAAI_adult values of 97.6% and 82.9%, respectively. This suggests that this species may have potential in potato breeding programmes and in human nutrition.     

Application of multidimensional scaling technique to differentiate sweet potato (Ipomoea batatas (L.) Lam) cultivars according to their chemical composition

Proximate composition (moisture, protein, starch, amylose, total dietary fibre, Brix degree, fat, ash, ascorbic acid, phenolic compounds, acidity and pH), minerals (Na, K, Ca, Mg) and trace elements (Fe, Cu, Mn, Zn) were determined in 30 cultivars of sweet potato from the Canary Islands (Spain). There were significant differences between the sweet potato cultivars for all the parameters studied; in addition, both the island of production and the cultivation cycle showed a noteworthy influence on the mineral and trace element composition of the tubers. It is worth mentioning that the consumption of sweet potatoes contributes relatively high intake levels of vitamin C, phenolic compounds and mineral and trace elements (K, Mg, Ca, Mn, Fe and Cu). Application of multidimensional scaling (MDS) correctly classified the sweet potato cultivars according to the island of production and maturation cycle.     

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.     

Gluten-free bread with an addition of freeze-dried red and purple potatoes as a source of phenolic compounds in gluten-free diet

The basis for gluten-free diet is often gluten-free bread, which is usually characterized by a low-nutritional value, and lacks any pro-health properties. Only after an introduction of gluten-free raw materials, containing high level of bioactive compounds it would be possible to obtain the product with a pro-health potential. The aim of the study was to analyze the content of bioactive compounds (total phenolic content, phenolic acids, flavonoids, flavonols, anthocyanins and carotenoids) in gluten-free bread prepared with 5% addition of freeze-dried red and purple potatoes as well as to assess their antioxidant potential. Summarizing, among the analyzed gluten-free breads with an addition of freeze-dried red and purple potatoes, the best results could be obtained by using variety Magenta Love (red potato), which provided the highest levels of phenolic compounds and carotenoids and also antioxidant and antiradical activity.     

Phenotypic, agronomic and nutritional characteristics of seven varieties of Andean potatoes

Potatoes are part of the staple food of Andean populations. Although there are more than 200 Andean potato varieties, only a few are cultivated at present, which endangers the biodiversity of the region. The objective of this paper was to characterize seven varieties of Andean potatoes (Collareja, Runa, Churqueña, Señorita, Imilla Colorada, Imilla Negra and Revolución) and to determine their phenotypic, functional and nutritional properties. The different varieties of Andean potatoes show differences in their agronomic properties, such as area of production and altitude yield per hectare, pest resistance and sowing and harvesting seasons. They are adapted to different altitudes, which influence their agronomic characteristics. Yield varies between 8000 and 18,000 kg/ha according to the variety. They present a diversity of forms, sizes and colors. The energy content ranges from 315 to 424 kJ/100 g, with these values being higher than those of the reference variety (239 kJ/100 g). Vitamin C content ranges from 10.5 mg/100 g found in Revolución varieties to 15.6 mg/100 g in Collareja potatoes; the vitamin C content in Spunta lies within this range (13.3 mg/100 g of potato). Increased knowledge of the nutritional, agronomic and functional properties of Andean potato varieties will contribute to the preservation of a biodiversity that is part of Argentina's regional heritage.     

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.     

Distribution of phenolic compounds and antioxidative activities in parts of sweet potato (Ipomoea batata L.) plants and in home processed roots

We measured six phenolic compounds by HPLC, the total phenolic content by Folin-Ciocalteu, and antioxidative activities by three methods in the sweet potato plant and in home processed roots. Total phenolic content was highest in the leaves. Eight root varieties were partitioned and analyzed for phenolics. The stem end of the root had significantly more phenolics. In all samples the predominant chlorogenic acids were 5-caffeoylquinic acid (5-CQA) and 3,5-diCQA. 3,4-diCQA was present in significant amounts in the leaves and the flower, and 4,5-diCQA in the leaves. Six home-processing/cooking techniques reduced phenolic content from 7% (baking) to ∼40% (deep frying/boiling). High correlations were observed between phenolic compounds determined by HPLC and Folin-Ciocalteu, radical scavenging activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH), and oxidative activity by ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods. The results show that there is a large variation in phenolics among sweet potato varieties and different parts of the plant and that high-phenolic sweet potato leaves, widely consumed in Asian countries as a vegetable, should be considered for diets of other countries.     

Physico-chemical properties and free amino acids profiles of six wolfberry cultivars in Zhongning

The physico-chemical properties and free amino acids profiles of six wolfberry cultivars from Zhongning County were characterized and compared. Fructose and glucose were found to be the predominant soluble sugars, citric acid was the most abundant organic acid. The values of total free amino acids (TFAA) were 278.07–505.12 mg/100 g FW, the essential amino acids accounted for 17 %–30 % of TFAA. NQ7 was the best for drying processing, because it showed moderate size, higher content of total carotenoids, betaine, tartaric acid, and citric acid, relatively high essential amino acids content, lower alkaline amino acids content and relatively low reducing soluble sugars content. Principal component analysis (PCA) allowed the six cultivars to be differentiated clearly based on all these physico-chemical properties and free amino acids profiles determined in the study.     

Application of a functional mathematical index (FMI) for predicting effects of the composition of jujube fruit on nutritional quality and health

In the present study, we extend the concept of a functional mathematical index (FMI), introduced in previous publications, for the assessment and prediction of food quality and safety of jujube fruit, a medicinal food widely consumed in Asian countries. In this study the index has been applied to one field-grown jujube fruit harvested at eight stages of maturity and three commercial Korean jujube cultivars. The index allows quantitative evaluation of nutritional, health-promoting, and safety aspects based on reported essential amino acid and phenolic content and antioxidative and cancer-cell-inhibiting activities of the test substances. For example, the FMI values for the antioxidative capacities ranged from 0.36 to 0.87 and for the inhibition normal and cancer cells from 0.35 to 0.86, suggesting that consumers have a choice of selecting growth (maturity) stages of jujube fruit with optimum beneficial properties. The use of specific performance FMI values seems to be a better tool for predicting relative beneficial and adverse effects than prediction on the basis of concentrations of the nutritional and bioactive compounds. The FMI approach, that numerically scores compositional, nutritional, and health-related aspects of food, complements but does not replace standard statistical analysis of the original compositional analytical data from which this value is derived. The method can be used to detect critical points during growth and processing of food that make it possible to optimize nutritional and health benefits.     

Plasma amino acids and cholesterol following consumption of dietary casein or soy protein in minipigs

Numerous investigators have claimed that protein-induced differences in plasma cholesterol are mediated by differences in amino acid composition. We have explored whether the venous postprandial amino acid profile reflects differences in the amino acid composition of the protein consumed. Six adult G?ttingen miniature pigs were fed a semisynthetic diet based on either casein or soy protein isolate. Frequent blood sampling was performed over a whole day after consumption of each diet for 6 wk. Postprandial plasma amino acid concentrations reached their maxima within the first 3 h. A group of eight protein amino acids (Met, Arg, Tyr, Val, Trp, Leu, Lys and Cys) exhibited the most marked and significant protein-dependent differences during this early postprandial phase, whereas Thr and His showed less marked differences. With one exception (Ser) all protein amino acids exhibited venous plasma concentration changes in qualitative accordance with their content in the dietary protein consumed. In quantitative terms, however, venous plasma amino acid changes were less marked than expected from the amino acid composition of the dietary proteins. We conclude that neither the considerable number of amino acids showing differences as reported herein nor the multitude of contradictory reported by others concerning single amino acids affecting serum cholesterol favor the hypothesis that one or several amino acid(s) cause protein-induced hypercholesterolemia.     

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.     

Influence of environment and genotype on polyphenol compounds and in vitro antioxidant capacity of native Andean potatoes (Solanum tuberosum L.)

The influence of environment and genetics on total phenolic content and hydrophilic antioxidant capacity (H-ORAC) of potato tubers was evaluated using 13 native Andean genotypes. Cultivars were grown at two highland locations in Peru: Huancayo and Huancani. Environmental conditions significantly affected the total phenolic contents and H-ORAC values in a cultivar-dependent manner. However, the potato genotype was the most determining factor of the observed variations. The effects of environment on individual phenolic compounds were also significant in terms of quantity, whereas the chemical profile remained stable across environmental conditions. To gain an insight into the observed antioxidant capacity of potato extracts, the individual and combined antioxidant effects of the main potato phenolic compounds were investigated. The ORAC values of reconstituted polyphenol mixtures reflecting the authentic phenolic composition of potato extracts were higher than expected from the summing of the ORAC values of individual phenolic compounds, indicating synergistic effects. The authentic potato extracts showed either a higher or a lower ORAC value than their reconstituted counterparts, suggesting positive or negative interactions with other compounds. Taken together, our results lead us to the following conclusions: (i) the hydrophilic antioxidant capacity observed in potato extracts is the result of various and complex interactions that could be attributed to phenolic compounds, to other non-identified molecules, and to synergistic as well as antagonistic effects between all these components and (ii) the high stability of the ranking of cultivars across environment in terms of phenolic content and antioxidant capacity indicates that the native Andean cultivars could be confidently used within breeding programs aiming at improving the health-promoting value of potato.     

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.     

Determination of free amino acids in beers: A comparison of Czech and foreign brands

The content of 16 free amino acids in 35 beers commercially available in Czech Republic was measured using high-performance liquid chromatography method with pre-column derivatization by AccQ·Tag agent and separation in reverse phase column followed by fluorescent detection. Content of proline, which was the amino acid most commonly found, varied in range from 40 to 250 mg/L. Czech beers were characterized by a significantly higher amino acid content in comparison to imported global brands (450.41±27.66 vs. 257.53±46.46 mg/L). Among individual amino acids, nine amino acids were significantly (p<0.01) more concentrated in the Czech beer brands than in the studied foreign brands, and those amino acids were from three distinctive taste groups: bitter tasting amino acid (isoleucine, leucine, lysine, phenylalanine and histidine), bitter sweet amino acids (valine and proline) and salty-umami amino acids (glutamic acid and aspartic acid).     

短肠综合征病人血清氨基酸谱的测定

目的:用高效液相色谱法检测短肠综合征病人的血清氨基酸谱. 方法:共测定17例短肠综合征病人的血清氨基酸谱,并以15例正常人空腹血作为对照,将异硫氰酸苯酯(PITC)作为柱前衍生剂,用甲醇、乙腈和乙酸钠作为二元梯度洗脱,67 min完成分离. 结果:17例短肠综合征病人血清缬氨酸、丝氨酸、胱氨酸非常显著低于正常人(P<0.01),血清亮氨酸、异亮氨酸、赖氨酸、蛋氨酸、组氨酸显著低于正常人(P<0.05). 结论:用高效液相色谱法检测氨基酸稳定可靠,短肠综合征病人存在氨基酸特别是必需氨基酸的缺乏.