Application of vibrational and fluorescence spectroscopy to the compositional analysis of colored-flesh potatoes.

BACKGROUND: Determination of composition and physicochemical parameters of natural products requires dedicated, often laborious and expensive, analytical protocols. Different spectroscopic techniques, in conjunction with chemometrics, seem to have a considerable potential in direct analysis of raw plant material and foods, without any chemical treatment. RESULTS: Fluorescence spectroscopy and three vibrational spectroscopy techniques were applied to determine total polyphenol content, antioxidant activity and macronutrient levels in red- and purple-fleshed potato varieties. Excitation-emission matrix fluorescence, Fourier transform Raman, attenuated total reflection Fourier transform infrared and near-infrared spectra were recorded for the freeze-dried samples. Combining spectral data and the results of reference analyses, partial least squares regression models were constructed for each parameter studied. For polyphenols and antioxidant activity, quantification errors found for validation samples amounted to 3.74-5.04% and 4.75-6.35%, respectively, whereas macronutrient analysis gave errors in the 3.45-4.55%, 3.09-5.30% and 5.10-8.58% ranges for starch, protein and sugar determinations, respectively. CONCLUSION: The obtained results demonstrate that different spectroscopic techniques in combination with multivariate modeling allow simultaneous determination of various parameters of plant samples based on a single sample spectrum. They can effectively replace commonly used protocols of food product analysis requiring sample dissolving and extraction of the compounds of interest. © 2023 Society of Chemical Industry.

Physicochemical parameters, sensory profile and concentration of volatile compounds and anthocyanins in beers brewed using potato variety with purple flesh.

In the recent years, beer brewers are experimenting with using various substrates, other than traditional barley malt, water, hops, and yeast for beer production, because new adjuncts to the beer brewing can add new sensory and functional properties to this beverage. Novel potatoes with purple or red-colour flesh are a good and cheap starch source and are rich in bioactive components, which could increase the nutritive value of the produced beer. The aim of the study was to determine whether some part of barley malt can be replaced by the potatoes of purple-colour flesh and assessment of properties of such beer. Beer samples showed increased antioxidant activity, higher concentration of anthocyanins and polyphenol compounds, as well as modified composition of volatiles and lower ethanol content. Beer produced with the addition of 30% of purple potatoes showed acceptable organoleptic qualities in the sensory analysis.

Quality and nutritional value of cookies enriched with plant-based protein preparations.

BACKGROUND: The objective of the study was to determine the effect of addition of plant-based protein preparations in cookie recipes on the quality and nutritional value of the obtained products. Wheat flour was replaced by 10%, 20% or 30% of pea, hemp seed, pumpkin and sunflower seed preparations. Baked cookies were analysed for chemical composition, amino acid profile, colour and texture as well as organoleptic attributes and overall acceptability. RESULTS: The addition of plant protein preparations improved the nutritional value of cookies by supplementing them with threonine and part of lysine. Replacing at least 20% of wheat flour with pea protein allowed the production of cookies with a well-balanced amino acid profile. The use of pea and sunflower proteins improved the appearance of the obtained products (consumer notes from 7.4 to 8.0) in comparison to the control sample (note 7.2). The physical properties of cookies were changed while organoleptic properties worsened. Cookies with the most desirable sensory values were obtained using the pea protein preparation. Acceptable cookies were also obtained with pumpkin and sunflower seed protein preparations, if the proportion of additive did not exceed 20% in relation to the amount of wheat flour. CONCLUSION: The use of protein preparations from pumpkin and sunflower as well as from hemp seeds allows the production of cookies with acceptable sensory characteristics that could diversify the range of cookie products. In the case of oilseed preparations, the amount of additive is limited primarily by the colour and taste of the finished products. © 2022 Society of Chemical Industry.

Comparative evaluation of the antioxidant, antimicrobial and nutritive properties of gluten-free flours.

Gluten-free flours are interesting alternative to wheat flours. They could be by-products of oilseed processing, characterized by high content of bioactive compounds. Therefore the aim of the study was to determine the antioxidant, antimicrobial properties, amino acid and fatty acid profile of flours obtained as by-products from the oil industry. The highest total polyphenol content and antioxidant activity was found to have evening primrose flour. The widest spectrum of microbial growth inhibition was indicated for corn germ extract which showed no antimicrobial activity only against Bacillus subtilis. The highest protein content was found in pumpkin, peanut and almond flours (more than 50 g/100 g). The major abundant amino acids in all the analysed oilseed cake flours were aspartic acid, glutamic acid and arginine. The analysed gluten-free flours were found to be a good source of polyunsaturated fatty acids (PUFAs), which comprised mainly linoleic acid and α-linolenic acid, whereas the best source of PUFAs was evening primrose flour. The results suggest that the cold-pressed seed flours possess valuable chemical composition and may be considered for improvement of the nutritional properties of food products.

Characterization of Bioactive Compounds of Opuntia ficus-indica (L.) Mill. Seeds from Spanish Cultivars.

Opuntia ficus-indica (L.) Mill. is the Cactaceae plant with the greatest economic relevance in the world. It can be used for medicinal purposes, animal nutrition, production of biofuels and phytoremediation of soils. Due to its high content of bioactive compounds, the prickly pear has antioxidant, antimicrobial and anticancer properties. The aim of this study was to determine the polyphenolic, fatty acid and amino acid profile and characterize the antioxidant capacity of seeds of seven Spanish prickly pear cultivars. A total of 21 metabolites, mainly phenolic acids and flavonols, were identified using ultraperformance liquid chromatography photodiode detector quadrupole/time-of-flight mass spectrometry (UPLC-PDA-Q/TOF-MS). Significant differences were found in the phenolic concentrations of the investigated varieties. The highest amount of phenolic compounds (266.67 mg/kg dry matter) were found in the "Nopal espinoso" variety, while the "Fresa" variety was characterized by the lowest content (34.07 mg/kg DM) of these compounds. In vitro antioxidant capacity was positively correlated with the amount of polyphenols. The amino acid composition of protein contained in prickly pear seeds was influenced by the variety. Glutamic acid was the predominant amino acid followed by arginine, aspartic acid and leucine, independent of prickly pear variety. Overall, 13 different fatty acids were identified and assessed in prickly pear seeds. The dominant fatty acid was linoleic acid, with content varying between 57.72% "Nopal ovalado" and 63.11% "Nopal espinoso".

Study of Antioxidant Activity of some Medicinal Plants Having High Content of Caffeic Acid Derivatives.

Recently, there has been increasing interest in medicinal plants, due to their content of health-promoting compounds, e.g., caffeic acids derivatives. Hence, the aim of this work was to study the antioxidant activity of extracts obtained from the following medicinal plants: caraway (Carum carvi L.), coltsfoot (Tussilago farfara L.), dandelion (Taraxacum officinale F.H.Wigg.), lovage (Levisticum officinale L.), tarragon (Artemisia dracunculus L.) and white mulberry (Morus alba L.), characterized by their high content of caffeic acid derivatives. The water-ethanolic extracts were characterized on average by about 9 times higher contents of caffeic acid derivatives level than water extracts. Both in water and water-ethanolic extracts, the dominant phenolic acid was 5-CQA (5-O-caffeoylquinic acid) and 3,4-diCQA (3,4-dicaffeoylquinic acid), then CCA-1 (chicoric acid isomer 1), which appeared only in water-ethanolic extracts. Extracts from dandelion contained compounds such as CTA (caftaric acid), CCA-1 (chicoric acid isomer 1) and CCA-2 (chicoric acid isomer 2), which were not detected in other plant extracts examined in this work. The water-ethanolic extracts from coltsfoot and tarragon were characterized by a high content of di-caffeoylquinic acids, especially 3,4-diCQA and 3,5-diCQA, respectively. It has been stated that there is a positive correlation between caffeic acid derivatives and antioxidant activity (radical cation scavenging activity (ABTS) and radical scavenging activity (DPPH)), especially in water-ethanolic extract of medicinal plants.

Determination of nutritional parameters of bee pollen by Raman and infrared spectroscopy.

Vibrational spectroscopy was applied to determine macronutrient levels, total polyphenols (TPs) content, antioxidant activity, pH and color parameters in bee pollens. Raman, attenuated total reflection and diffuse reflectance spectra in the mid- and near-infrared regions were recorded for the homogenized pollen granules. Combining spectral data and the results of reference analyses, partial least squares (PLS) models were constructed and validated. The relative standard errors of prediction (RSEP) were calculated for the calibration and validation sets. Regarding macronutrient analysis, the latter were found to be in the 1.7-2.3%, 2.5-3.6% and 2.6-3.3% ranges for protein, reducing sugars and fat determination, respectively. These errors amounted to 3.1-3.5% for TPs and 2.2-3.4% for antioxidant activity quantification, respectively, whereas they were found to be in the 1.5-2.3% and 1.6-3.2% ranges for pH and the color parameters' determination.

The effect of frying on glycidyl esters content in palm oil.

The changes in palm oil, as affected by frying temperature, and content of the glycidyl esters (GEs) were studied. Potato chips were fried intermittently in palm oil, which was heated for 8 h daily over five consecutive days. Frying was conducted at three frying temperatures: 150, 165 and 180 °C. Thermo-oxidative alterations of the oil were measured by acid and anisidine values, changes in fatty acid composition, total polar components, polar fraction composition and colour components formation. Content of GE was measured by liquid chromatography-mass spectrometry. Results showed that amount of products of hydrolysis, oxidation and polymerization (excluding decrease of degree of unsaturation) increased significantly as a function of frying temperature and time. Between GEs of fatty acids the most abundant were esters of palmitic and oleic acids. With increasing temperature and frying time, the content of GE decreased. The extent of GE decrease was correlated with degree of oil degradation.

The effect of raw materials on thermo-oxidative stability and glycidyl ester content of palm oil during frying.

BACKGROUND: The objective of this research was to determine the effects of the water content of food incorporated into frying oil on oil degradation and the content of glycidyl esters. Potato chips, French fries and snacks were fried intermittently in palm oil, which was heated at 180 °C for 8 h per day over five consecutive days. Thermo-oxidative and physical alterations, changes in fatty acid composition, total polar components, polar fraction composition, and water content were analysed. The content of glycidyl esters was measured by liquid chromatography-tandem mass spectrometry. RESULTS: More polar compounds were formed in the oil used for frying chips (252 g kg(-1)) than for French fries (229 g kg(-1)) or snacks (196 g kg(-1)). Reductions in glycidyl esters were found in oils used for frying--greater for frying snacks and French fries (95% and 93%) than for potato chips (87%). The rate of decrease of glycidyl esters was correlated with frying parameters, most strongly with the concentrations of diacylglycerols (r = 0.98) and total polar components (r = -0.98). CONCLUSION: The raw material had a greater influence on polymerization conversion and glycidyl ester content than on hydrolytic and oxidative changes in the frying oil.

Monitoring of glycidyl fatty acid esters in refined vegetable oils from retail outlets by LC-MS.

BACKGROUND: Glycidyl fatty acid esters (GEs) are a newly identified class of food process contaminants. The main source of these compounds is refined oils. Because of the potential release of free glycidol, it is necessary to enable a more accurate exposure assessment. In this study a method based on liquid chromatography-single-quadrupole mass spectrometry was used for the analysis of GEs in refined vegetable oils from retail outlets in Poland. RESULTS: The amount of GEs detected in 20 edible oils ranged from 0.00 to 44.33 mg kg(-1) . Refined palm oils exhibited a several times higher contamination ratio in comparison with other oils (average 31.24 mg kg(-1) ). The average content of esters in sunflower oils (2.46 mg kg(-1) ) was higher than in rapeseed oils (1.04 mg kg(-1) ). C18:2-GE was found to be the prevailing GE in sunflower oil, with the highest concentration in all studied samples, while C18:1-GE was the prevailing GE in rapeseed and palm oils. No trace of C18:3-GE was found in the analysed oils. CONCLUSION: The concentrations of major GEs were correlated with the fatty acid composition of the oils. The GE content varied with the type of oil and the producer. The tested oils had a higher or similar GE content compared with those analysed by other researchers. © 2015 Society of Chemical Industry.

Npvf: Hypothalamic Biomarker of Ambient Temperature Independent of Nutritional Status.

The mechanism by which mice, exposed to the cold, mobilize endogenous or exogenous fuel sources for heat production is unknown. To address this issue we carried out experiments using 3 models of obesity in mice: C57BL/6J+/+ (wild-type B6) mice with variable susceptibility to obesity in response to being fed a high-fat diet (HFD), B6. Ucp1-/- mice with variable diet-induced obesity (DIO) and a deficiency in brown fat thermogenesis and B6. Lep-/- with defects in thermogenesis, fat mobilization and hyperphagia. Mice were exposed to the cold and monitored for changes in food intake and body composition to determine their energy balance phenotype. Upon cold exposure wild-type B6 and Ucp1-/- mice with diet-induced obesity burned endogenous fat in direct proportion to their fat reserves and changes in food intake were inversely related to fat mass, whereas leptin-deficient and lean wild-type B6 mice fed a chow diet depended on increased food intake to fuel thermogenesis. Analysis of gene expression in the hypothalamus to uncover a central regulatory mechanism revealed suppression of the Npvf gene in a manner that depends on the reduced ambient temperature and degree of exposure to the cold, but not on adiposity, leptin levels, food intake or functional brown fat.

Anthocyanin and antioxidant activity of snacks with coloured potato.

Coloured-fleshed potatoes of four varieties were used as raw material for coloured flour and fried snack production. The effects of thermal processes traditionally used in dried potato processing and in snack pellet manufacturing on anthocyanin profiles, total polyphenols and antioxidant properties of obtained half- and ready products were studied. There was a significant influence of potato variety on the experimental flour and snack properties. Flours with the highest antioxidant activities were obtained from Salad Blue and Herbie 26 potatoes; however, the flour prepared from the Blue Congo exhibited a much higher total polyphenol and anthocyanin content. Snacks produced with coloured flour had 2-3 times higher antioxidant activities, 40% higher contents of polyphenols, attractive colour and better expansion compared to control samples. The lowest losses of anthocyanins during snack processing were in snacks with flour from the purple-fleshed Blue Congo and red-fleshed Herbie 26.

Characteristics of antioxidant activity and composition of pumpkin seed oils in 12 cultivars.

The objective of this study was to determine the antioxidant properties, and provide characteristics, of the oil obtained from the seeds of 12 pumpkin varieties belonging to the species Cucurbita maxima Duch. and Cucurbita pepo L. Another objective was to establish which of the two extracting agents, ethanol or methanol, is more effective. The seeds of the pumpkin varieties examined differ in chemical composition and antioxidant activity. The seeds of the cultivars belonging to the species C. maxima are characterised by a higher content of fatty acids than are the cultivars of the species C. pepo. In the seed oil, unsaturated acids are dominant (oleic and linoleic), and their proportion depends on the pumpkin variety. The highest content of unsaturated acids has been measured in the oil extracted from the seeds of the cultivar, Jet F1 (C. pepo). Antioxidant activity analysis has produced the following findings. The seeds of the pumpkin varieties that belong to the species C. pepo exhibit better antioxidant properties, regardless of the extraction solvent used. 50% ethanol is more efficient than 80% methanol when used as an extracting agent. The antioxidant activity values obtained with 50% ethanol are higher than those achieved with 80% methanol. Owing to the considerable differences in composition among the fatty acids examined, it is possible to choose the desired pumpkin variety for the intended use.

Screening of acrylamide contents in potato crisps using process variable settings and near-infrared spectroscopy.

In order to study the formation of acrylamide in potato crisps during processing, an experimental design was set up. The design variables were drying time (6 levels), frying temperature (2 levels) and frying time (8 levels). The design contained 36 samples, which were analysed for acrylamide contents using LC high-resolution mass spectroscopy (LC-HRMS), and fat contents using the Soxhlet apparatus. Prior to analysis, all potato crisp samples were ground and analysed on an NIRSystems 6500 near-infrared (NIR) spectrometer. The acrylamide contents were modelled by: (i) design variables using multiple linear regression, (ii) NIR spectra using partial least squares regression (PLSR) and (iii) design variables and NIR spectra in combination using a novel technique combining least squares regression on the former, and PLSR on the latter. The results showed that the NIR spectra alone or in combination with the design variables gave better prediction models for acrylamide than the design variables alone. This implies that the spectra contain chemical information that is not purely a result of the processing variables that were investigated in this experiment. NIR spectroscopy is proposed as a possible tool for screening and identification of potato crisps with a high acrylamide content.

Addition of glycine reduces the content of acrylamide in cereal and potato products.

The effects of adding amino acids on the content of acrylamide in potato crisps, French fries, flat breads, and bread crusts were investigated. Addition of glycine or glutamine during blanching of crisps reduced the amount of acrylamide by approximately 30% compared to no addition. No effect was found in French fries. Addition of glycine during doughmaking significantly reduced acrylamide in both flat breads and bread crusts. In bread crusts the reduction of acrylamide ranged from 50 to >90% depending on the baking condition. In flat breads the reduction varied between 60 and >95%.

Effective ways of decreasing acrylamide content in potato crisps during processing.

The aim of this work was to examine the effect of blanching or soaking in different acid solutions on the acrylamide content in potato crisps. Furthermore, the effects of a shorter frying time and a lower frying temperature combined with a postdrying were investigated. Soaking or blanching of potato slices in acidic solutions decreased the pH of potato juice and increased the extraction of amino acids and sugars. Potato crisps obtained after such pretreatments were characterized by lower acrylamide content. The most effective extraction of free amino acids and sugars as well as the largest decrease of acrylamide content (90%) in crisps was obtained when potato slices were soaked in acetic acid solution for 60 min at 20 degrees C. Shorter frying time followed by postdrying resulted in low-moisture potato crisps. Furthermore, the postdrying treatment gave a decreases in acrylamide content of approximately 70% when potato slices were fried at 185 degrees C and approximately 80% when potato slices were fried at 160 degrees C. Effective ways of decreasing acrylamide content in crisps production have been found. Crisps with low acrylamide content and good sensory quality can be obtained either by blanching in acetic acid as pretreatment or by a short frying followed by postdrying.