Glycoalkaloid Levels Research Articles

Changes in the Levels of Glycoalkaloids and Nitrates After the Dehydration of Cooked Potatoes

The aim of this study was to investigate the effects of various processes used during the laboratory production of dehydrated cooked potato on the concentration of glycoalkaloids (α-chaconine and α-solanine) and nitrates in the raw material, intermediate and final product. In the raw material, half-products and in the final products there were determined glycoalkaloids contents (α-chaconine and α-solanine) with the use of HPLC method and nitrates contents colorimetrically by RQflex apparatus. During the laboratory production of dehydrated potato, glycoalkaloid and nitrate content in processed potatoes decreased. TGA decreased most after peeling (30 %), blanching (28 %) and pre-drying (25 %). Nitrate content decreased significantly after blanching (21 %) and after pre-drying (18 %).

The Impact of γ-Irradiation, Essential Oils and Iodine on Biochemical Components and Metabolism of Potato Tubers During Storage

Several methods have been suggested as effective for inhibition of sprouting of potato tubers during storage. Three methods; γ-irradiation, volatile oils and iodine vapor were used for the inhibition of potato tuber cv. ‘Diamond’. Gamma irradiation, essential oils (caraway, clove, carvone, eugenol) and Iodine vapor were used to achieve the purpose. The results proved that γ-irradiation and essential oils maintain potato as well as inhibit sprouting for 9 weeks while iodine vapor maintain potato for six weeks. Alpha amylase activity showed an increase after six weeks and then reduced to lower value compared to control. During the metabolic pathway the concentration of lactate was decreased and reached to the level of control when potato tuber treated even with essential oils, radiation as well as with iodine vapor. The levels of NADP and NADPH+H were decreased during potato storage proving that synthesis of this metabolite were very low. The level of glycoalkaloids was fluctuated during storage depending on the treatments.

Feeding fish according to organic aquaculture guidelines EC 710/2009: Influence of potato protein concentrates containing various glycoalkaloid levels on health status and growth performance of rainbow trout ( Oncorhynchus mykiss)

A feeding trial was conducted to evaluate the effect of potato protein concentrate (PPC) replacing fishmeal in nutrition of rainbow trout ( Oncorhynchus mykiss) according to organic aquaculture guidelines. Eight diets were formulated by partial replacement of fishmeal (25%, 50%, 75% and 100%) with PPC of two different qualities (LG-PPC with low glycoalkaloid content of 7.41 mg kg − 1 dry weight, HG-PPC with high glycoalkaloid content of 2150 mg kg − 1 dry weight) and one experimental diet without PPC served as control. Experimental diets were fed over a period of 84 days to triplicate experimental groups until apparent satiation. Best growth performance was observed in the control group. The inclusion of LG-PPC resulted in significantly reduced feed intake, feed utilization and growth with increasing replacement of 25% and higher. Increasing amount of dietary LG-PPC inclusion resulted in alterations in liver histology and in anterior intestine indicating an impact of glycoalkaloids on the different gastrointestinal tissues. The HG replacement revealed most prominently a decreased feed intake and growth parameters indicating massive undernourishment. Congruently, hypotrophy of the liver with ceroid pigment accumulation, and villi degeneration in the intestine were observed in all HG groups. Blood parameters were equally affected by an inclusion of PPC (LG and HG) in the diets involving reduced plasma TG (HG75), glucose (HG100) as well as protein (HG100). As a conclusion PPC as alternative protein in fish nutrition is only feasible with LG contents as HG diets resulted in severe undernourishment of fish, lowest growth performance and irreversible intestinal damages.

Germplasm Release: Tetraploid Clones with Resistance to Cold-Induced Sweetening

Long-term cold storage is necessary to supply potatoes to the processing industry throughout the year. Cold-induced sweetening prevents current potato cultivars from producing acceptable chips after cold storage. Resistance to cold-induced sweetening has been introgressed into the cultivated potato from wild Solanum relatives. This paper describes five tetraploid interspecific hybrid clones that can be used in breeding programs to improve chip quality in cold-stored tubers. The clones are male and female fertile, and are adapted to temperate zone production environments. All clones except M1 have low levels of glycoalkaloids. They produce acceptable chip color following storage at 4.4°C for 3 months. Tubers from all clones have high specific gravity. Following cold storage, tuber glucose and fructose contents are low compared to standard cultivars. Tuber sucrose contents for the five clones are either comparable to that in standard cultivars or much greater.

The Role of Organic Acids in the Domestication of Oxalis tuberosa: A New Model for Studying Domestication Resulting in Opposing Crop Phenotypes1

The Role of Organic Acids in the Domestication ofOxalis tuberosa: A New Model for Studying Domestication Resulting in Opposing Crop Phenotypes. Though few crops display directly opposing domesticated phenotypes, these crops may be the key to understanding domestication processes that address conflicting selective pressures in the agricultural ecosystem. Two relatively well-known examples are cassava (Manihot esculenta Crantz), which has high-cyanide and low-cyanide varieties, and potato (Solanum section Petota). Among the potatoes are several species, including the common potato (Solanum tuberosum L.), that have low levels of glycoalkaloids and there are other species of “bitter potato” with elevated levels of glycoalkaloids. We propose that Oxalis tuberosa Molina, “oca,” may represent a third example of such a crop system, with opposing high organic acid and low organic acid cultivars. Each cultivar set has different cultural food preparation practices (“use-categories”), similar to the “use-categories” that have been described for potatoes in the Andes (Brush et al. Economic Botany 35;70–88, 1981; Zimmerer Journal of Biogeography 18;165–178, 1991). Our initial analyses suggest that organic acids in tubers may be an important biochemical difference between use-categories, based on both oxalic acid and pH data. Here, we review our understanding of organic acids in oca tubers, while highlighting areas that merit further investigation.

α-Solasonine and α-Solamargine Contents of Gboma (Solanum macrocarpon L.) and Scarlet (Solanum aethiopicum L.) Eggplants

The gboma (Solanum macrocarpon L.) and scarlet eggplants (Solanum aethiopicum L.), which form part of the traditional sub-Saharan African culture, are two of the many neglected crops with potential for increased cultivation or as a genetic resource for improving agronomic traits of the common eggplant. This work is focused on the analysis of glycoalkaloid levels in S. macrocarpon and S. aethiopicum to assess their safety. Liquid chromatography-mass spectrometry was used to quantify glycoalkaloids in S. macrocarpon and S. aethiopicum compared to Solanum melongena L. Fruits of S. aethiopicum and S. melongena contained 0.58-4.56 mg/100 g of alpha-solamargine and 0.17-1 mg/100 g of alpha-solasonine, on a wet basis. S. macrocarpon fruits had much higher values of alpha-solamargine (124-197 mg/100 g) and alpha-solasonine (16-23 mg/100 g). However, the proportions of alpha-solamargine and alpha-solasonine of S. melongena and S. macrocarpon were similar (76-89% of alpha-solamargine), whereas in S. aethiopicum fruit composition was more variable (48-89% of alpha-solamargine). According to these results, the glycoalkaloid levels of S. macrocarpon fruits are 5-10 times higher than the value considered to be safe in foods and might not be considered suitable for human consumption; however, the glycoalkaloid levels of S. aethiopicum were similar to those of S. melongena (about 14% of values considered as toxic) and could be considered as safe for consumption. The incorporation of the cultivated African S. aethiopicum into eggplant breeding programs to develop improved varieties of the common eggplant may represent an alternative to crossing with wild species.

Naturally Occurring Glycoalkaloids in Potatoes Aggravate Intestinal Inflammation in Two Mouse Models of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) may be initiated following disruption of the intestinal epithelial barrier. This disruption, in turn, permits luminal antigens unfettered access to the mucosal immune system and leads to an uncontrolled inflammatory response. Glycoalkaloids, which are found in potatoes, disrupt cholesterol-containing membranes such as those of the intestinal epithelium. Glycoalkaloid ingestion through potatoes may play a role in the initiation and/or perpetuation of IBD. To determine if commercial and high glycoalkaloids containing fried potato skins aggravate intestinal inflammation using two different animal models of IBD. Fried potato skins from commercial potatoes containing low/medium glycoalkaloid levels and high glycoalkaloids potatoes were fed for 20 days to interleukin 10 gene-deficient mice and dextran sodium sulfate-induced colitic mice. Intestinal permeability, mucosal cytokine and myeloperoxidase levels and body weight were determined to assess intestinal injury. Deep frying potato skins markedly increased glycoalkaloid content. Interleukin 10 gene-deficient mice fed fried commercial potato skins with medium glycoalkaloid content exhibited significantly elevated levels of ileal IFN-γ relative to controls. Mice in the dextran sodium sulfate colitis model that were fed the same strain of potatoes demonstrated significantly elevated levels of pro-inflammatory cytokines IFN-γ, TNF-α, and IL-17 in the colon in addition to an enhanced colonic permeability. Inflammatory response was intensified when the mice were fed potatoes with higher glycoalkaloid contents. Our results demonstrate that consumption of potato skins containing glycoalkaloids can significantly aggravate intestinal inflammation in predisposed individuals.

Distortion of trichome morphology by the hairless mutation of tomato affects leaf surface chemistry

Trichomes are specialized epidermal structures that function as physical and chemical deterrents against arthropod herbivores. Aerial tissues of cultivated tomato (Solanum lycopersicum) are populated by several morphologically distinct trichome types, the most abundant of which is the type VI glandular trichome that produces various specialized metabolites. Here, the effect of the hairless (hl) mutation on trichome density and morphology, chemical composition, and resistance to a natural insect herbivore of tomato was investigated. The results show that the major effect of hl on pubescence results from structural distortion (bending and swelling) of all trichome types in aerial tissues. Leaf surface extracts and isolated type VI glands from hl plants contained wild-type levels of monoterpenes, glycoalkaloids, and acyl sugars, but were deficient in sesquiterpene and polyphenolic compounds implicated in anti-insect defence. No-choice bioassays showed that hl plants are compromised in resistance to the specialist herbivore Manduca sexta. These results establish a link between the morphology and chemical composition of glandular trichomes in cultivated tomato, and show that hl-mediated changes in these leaf surface traits correlate with decreased resistance to insect herbivory.

Glycoalkaloid content of some superior potato (Solanum tuberosum L) clones and commercial cultivars

Glycoalkaloids are important metabolites in potato because of their toxic properties and potential harmful effects to humans. To validate a rapid assay to determine and quantify glycoalkaloid content and its distribution in potato tubers, we have characterized and quantified, by HPLC and by colorimetry with bromphenol blue, the glycoalkaloids in 15 potato cultivars and experimental clones grown in the tropical climate of Kenya. There was significant correlation of TGA by HPLC and colorimetry. Significant differences in glycoalkaloid content were detected among potato cultivars. The concentration of α-chaconine in the 15 cultivars ranged from 1.62 to 4.46 mg/100 g fresh weight (fwt), of α-solanine from 1.45 to 4.51 mg/100 g, and of solanidine from 1.58 to 5.21 mg/100 g. Total glycoalkaloid values (TGA, sum of the three compounds) for the 15 cultivars determined by HPLC ranged from 5.31 to 15.39 mg/100 g and the corresponding values determined by bromphenol blue colorimetry, from 3.51 to 17.48 mg/100 g. Dutch Robijn, a late blight susceptible cultivar under Kenyan conditions had the lowest level (3.51 mg/100 g) of total glycoalkaloids and Tigoni, a late blight resistant cultivar, had the highest amount (15.97 mg/100 g). In contrast to most previous studies, high levels of solanidine in tubers of tropical-climate adapted cultivars were recorded in our experiments. The dietary significance of a high amount of solanidine in the cultivars has not been previously reported and deserves further study.

A Test of Taxonomic Predictivity: Resistance to the Colorado Potato Beetle in Wild Relatives of Cultivated Potato

Wild relatives of potato offer a tremendous germplasm resource for breeders. Because the germplasm base of potato is so broad and diverse, we have undertaken a series of studies to determine whether we can predict the distribution of valuable genes in wild Solanum species based on taxonomic or biogeographic data. This is the third study in the series. Resistance to defoliation by Colorado potato beetle, Leptinotarsa decemlineata Say, larvae was evaluated in 156 accessions of 41 wild Solanum species. The highest frequencies of resistant accessions were found in diploid species with an endosperm balance number of 1. In contrast to previous studies on resistance to foliar fungal pathogens, there was little variability in defoliation scores among plants within an accession and among accessions within a species, at least for the most resistant species. There was no strong association of Colorado potato beetle resistance in wild potato species to biogeographic data. Resistance was confirmed in species previously characterized by high levels of glycoalkaloids or dense glandular trichomes. However, we have identified additional species with resistance to the Colorado potato beetle. Mechanisms of resistance are being studied in these species and attempts will be made to introgress them into the cultivated potato.

Modification of the Health-Promoting Value of Potato Tubers Field Grown under Drought Stress: Emphasis on Dietary Antioxidant and Glycoalkaloid Contents in Five Native Andean Cultivars (Solanum tuberosum L.)

The effects of drought stress on dietary antioxidant and glycoalkaloid contents in potato tubers were investigated using a selection of five native Andean cultivars. Both freshly harvested and 4 month-stored tubers were analyzed. Responses to drought stress were highly cultivar-specific. The antioxidant contents of the yellow tuber-bearing cultivars (Sipancachi and SS-2613) were weakly affected by the drought treatment, whereas the pigmented cultivars demonstrated highly cultivar-dependent variations. A drastic reduction of anthocyanins and other polyphenols was revealed in the red- (Sullu) and purple-fleshed (Guincho Negra) cultivars, whereas an increase was shown in the purple-skinned and yellow-fleshed cultivar (Huata Colorada). The hydrophilic antioxidant capacity (evaluated by Folin-Ciocalteu and H-oxygen radical absorbance capacity assays) was highly correlated with the polyphenol content and followed, therefore, the same behavior upon drought. Carotenoid contents, including beta-carotene, as well as vitamin E, tended to increase or remain stable following drought exposure, except for the cultivar Sullu, in which the level of these lipophilic antioxidants was decreased. Vitamin C contents were not affected by drought with the exception of Guincho Negra, in which the level was increased. These variations of health-promoting compounds were associated with increased or stable levels of the toxic glycoalkaloids, alpha-solanine and alpha-chaconine. Storage at 10 degrees C for 4 months tended to decrease the concentrations of all dietary antioxidants, except those of vitamin E. This storage also reduced the drought-induced variations observed in freshly harvested tubers. These results were discussed in terms of their implications for human diet and health as well as in plant stress defense mechanisms.

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.

A major QTL and an SSR marker associated with glycoalkaloid content in potato tubers from Solanum tuberosum × S. sparsipilum located on chromosome I

New potato (Solanum tuberosum) varieties are required to contain low levels of the toxic glycoalkaloids and a potential approach to obtain this is through marker-assisted selection (MAS). Before applying MAS it is necessary to map quantitative trait loci (QTLs) for glycoalkaloid content in potato tubers and identify markers that link tightly to this trait. In this study, tubers of a dihaploid BC(1) population, originating from a cross between 90-HAF-01 (S. tuberosum(1)) and 90-HAG-15 (S. tuberosum(2) x S. sparsipilum), were evaluated for content of alpha-solanine and alpha-chaconine (total glycoalkaloid, TGA) after field trials. In addition, tubers were assayed for TGA content after exposure to light. A detailed analysis of segregation patterns indicated that a major QTL is responsible for the TGA content in tubers of this potato population. One highly significant QTL was mapped to chromosome I of the HAG and the HAF parent. Quantitative trait loci for glycoalkaloid production in foliage of different Solanum species have previously been mapped to this chromosome. In the present research, QTLs for alpha-solanine and alpha-chaconine content were mapped to the same location as for TGA content. Similar results were observed for tubers exposed to light. The simple sequence repeat marker STM5136 was closely linked to the identified QTL.

Changes in the content of glycoalkaloids in potato tubers according to soil tillage and weed control methods

A field experiment was carried out in the fields of the Experimental Farm in Zawady owned by the University of Podlasie in Siedlce. An influence of soil tillage methods and herbicides application on the content of glycoalkaloids in edible potato tubers of the Viking cultivar was studied. The results obtained indicated that the content of glycoalkaloids in non-peeled tubers significantly depended on the method of soil tillage and weed control as well as on the research year, whereas in peeled tubers the content significantly depended only on the weather conditions in the growing season. The content of glycoalkaloids in the tubers subjected to the initial treatment (peeling) decreased to 46.81−55.3%, compared to the level of glycoalkaloids before peeling.

Variability in host plant chemistry: behavioural responses and life-history parameters of the Colorado potato beetle (Leptinotarsa decemlineata)

Many studies investigating effects of plant chemicals on herbivore performance have reported contradictory results, perhaps because of possible interaction between different chemicals. Also, a herbivore’s performance is not necessarily consistent with its food or oviposition preference. Our aim was to investigate simultaneously antibiosis (larval growth and survival) and antixenosis (oviposition and feeding preferences) responses in herbivore to three plant chemicals, of which one is expected to have positive and two are expected to have negative effects. Antibiosis was measured by correlating the nitrogen and glycoalkaloid levels in host plants to the survival and adult size of Leptinotarsa decemlineata, by rearing larvae on whole plants of three potato varieties. Although host plants differed in their glycoalkaloid levels, survival rate and adult body size did not differ among beetles reared on different potato varieties. This suggests that beetles are quite robust for differences in both foliar α-chaconine and foliar α-solanine content. However, differences in antixenosis were found although they could not be directly predicted from the leaf chemistry. Females preferred to lay their eggs on the variety with high α-solanine content (Nevsky) towards which males showed a tendency to feeding preference. Overall, our results confirm that beetles are well adapted to the chemical defences of potato plants as potato varieties did not significantly affect beetle performance, but differences in oviposition preference may still result in major differences in the amount of damage inflicted on plants in the fields.

Dakota Pearl: An attractive, bright white-skinned, cold-chipping cultivar with tablestock potential

Dakota Pearl (ND2676-10) is a medium-maturing chipping cultivar with uniform, round, bright white-skinned tubers with shallow eyes. Dakota Pearl has the ability to produce commercially acceptable chips following long-term storage at 5.5 C without the need for reconditioning. It yields well under both dryland and irrigated trial conditions in North Dakota. North Central Regional Potato Variety Trial and Snack Food Association Trial results indicate it has wide adaptability. Yield and specific gravity under dryland conditions are similar to Norchip; Dakota Pearl has a low percentage of external defects. Average set is 12 to 14 tubers per hill. Dakota Pearl demonstrates wide consumer appeal as a tablestock cultivar due to attractive tuber appearance and bright-white skin. Sensory evaluation scores for baking, boiling, and microwaving are comparable to those of standard chip cvs Atlantic, NorValley, and Snowden. The specific gravity of Dakota Pearl is similar to cvs Norchip and NorValley, lower than for Atlantic or Snowden. Total glycoalkaloid levels are low, at 1.5 mg/100 g fresh tuber tissue. The North Dakota Agricultural Experiment Station released Dakota Pearl on 23 April 1999.

Sensory Quality Ratings and Mineral and Glycoalkaloid Concentrations in Organically and Conventionally Grown Redskin Potatoes (Solanumtuberosum)

Sensory evaluations (triangle tests) were used to determine if panelists could distinguish, by tasting, cooked wedges of potatoes grown organically, either with or without compost, and conventionally. Mineral and glycoalkaloid analyses of tuber skin and flesh were also conducted. When the skin remained on the potatoes, panelists detected differences between conventional potatoes and organic potatoes, regardless of soil treatment. However, they did not distinguish between organic treatments (±compost) when samples contained skin or between any treatments if wedges were peeled prior to preparation. Glycoalkaloid levels tended to be higher in organic potatoes. In tuber skin and flesh, potassium, magnesium, phosphorus, sulfur, and copper concentrations were also significantly higher in the organic treatments, while iron and manganese concentrations were higher in the skin of conventionally grown potatoes.

Sensory quality and mineral and glycoalkaloid concentrations in organically and conventionally grown redskin potatoes (Solanum tuberosum)

AbstractTriangle tests were used to determine if panellists could distinguish (by tasting) cooked wedges of potatoes grown organically, either with (+) or without (−) compost, and conventionally. Mineral and glycoalkaloid analyses of tuber skin and flesh were also completed. When the skin remained on the potatoes, panellists detected differences between conventional potatoes and organic potatoes, regardless of soil treatment. However, they did not distinguish between organic treatments (± compost) when samples contained skin, or between any treatments if wedges were peeled prior to preparation and presentation. Glycoalkaloid levels tended to be higher in organic potatoes. In tuber skin and flesh, potassium, magnesium, phosphorus, sulfur and copper concentrations were also significantly higher in the organic treatments, while iron and manganese concentrations were higher in the skin of conventionally grown potatoes. Copyright © 2005 Society of Chemical Industry

Quality and safety evaluation of genetically modified potatoes spunta with Cry V gene: compositional analysis, determination of some toxins, antinutrients compounds and feeding study in rats.

The aim of this study was to evaluate the composition, nutritional and toxicology safety of GM potato Spunta lines compared to that of conventional potato Spunta. Compositional analyses were conducted to measure the proximate chemical composition with references to 14 components, total solid, protein, lipid, crude fibre, ash, carbohydrate, starch, reducing sugar, nonreducing sugar, sodium, calcium, potassium, phosphorus, and ascorbic acid. Some toxins and anti-nutrients compounds were determined. Feeding study of GM potatoes line (G2 and G3) in rats were done for 30 days. Four groups of albino rats were used for studying the effect and the safety assessment of GM potatoes Spunta G2 and G3. Group (I) was fed on control basal diet, group (II) was fed on control diet plus 30% freeze-dried nongenetically modified potato Spunta, group (III) was fed on control diet plus 30% freeze-dried genetically modified potato Spunta, and group (IV) was fed on control diet plus 30% freeze-dried genetically modified potato Spunta GMO G3. There were no significant differences between GM potatoes G2, G3, and Spunta control potato line in the proximate chemical composition. The levels of glycoalkaloids in transgenic potato tubers and nontransgenic were determined and there were also no significant differences between the GM potatoes and conventional potato line, the levels were in agreement with a safety level recommended by FAO/WHO (200 mg/ kg) for acute toxicity. Protease inhibitor activity and total phenol were estimated and no significant differences between the GM potatoes line and conventional potato Spunta line were found. During the period tested, rats in each group (I, II, III, IV) grew well without marked differences in appearance. No statistical difference were found in food intake, daily body weight gain and feed efficiency. But there is a slightly significant difference in finally body weight between the control group and experimental groups. No significant difference were found in serum biochemical value between each groups, and also between relative organs weight (liver, spleen, heart, kidney, testes). From these results, it can be concluded that the GM potatoes Spunta line (G2 and G3) with Cry V gene are confirmed to have nearly the composition and biochemical characteristics as non-GM potato Spunta.

The effect of storage conditions (temperature, light, time) and variety on the glycoalkaloid content of potato tubers and sprouts

The effects of variety, tuber group, storage period and storage type on glycoalkaloid levels of potato tubers and sprouts were investigated. Normal, wounded and greened tubers and sprouts from potatoes of varieties Marfona and Granola were analysed for α-solanine, α-chaconine and total glycoalkaloid concentration by using HPLC. The potatoes were stored in normal store light, normal store dark, retail refrigerator light, and retail refrigerator dark. Analyses were carried out at the beginning, 3rd and 6th months for the potatoes, and at 6th month for the sprouts. The tubers had an α-solanine content ranging from 0.01 to 6.46 mg/kg FW, α-chaconine content from 0.35 to 28.12 mg/kg FW and total glycoalkaloid content from 0.66 to 32.76 mg/kg FW.