Influence of Roasting Temperature on the Detectability of Potentially Allergenic Lupin by SDS-PAGE, ELISAs, LC-MS/MS, and Real-Time PCR.

Seeds of "sweet lupins" have been playing an increasing role in the food industry. Lupin proteins may be used for producing a variety of foods, including pasta, bread, cookies, dairy products, and coffee substitutes. In a small percentage of the population, lupin consumption may elicit allergic reactions, either due to primary sensitization to lupin or due to cross-allergy with other legumes. Thus, lupin has to be declared on commercial food products according to EU food regulations. In this study, we investigated the influence of roasting seeds of the L. angustifolius cultivar "Boregine" on the detectability of lupin by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), ELISAs, LC-MS/MS, and real-time PCR. Seeds were roasted by fluidized bed roasting, and samples were drawn at seed surface temperatures ranging from 98 °C to 242 °C. With increasing roasting temperature, the extractability of proteins and DNA decreased. In addition, roasting resulted in lower detectability of lupin proteins by ELISAs and LC-MS/MS and lower detectability of DNA by real-time PCR. Our results suggest reduced allergenicity of roasted lupin seeds used for the production of "lupin coffee"; however, this has to be confirmed in in vivo studies.

Physicochemical Attributes, Aroma Profile, and Sensory Quality of Organic Crimson Crisp Apples after Storage.

The objective of this study was to determine the effect of various storage conditions (i.e., storage under regular air with temperature control, controlled atmosphere storage and storage after the application of the ethylene blocker (1-MCP)) on the flavor characteristics of Crimson Crisp apples (Malus domestica Borkh.), a scab-resistant cultivar suitable for organic agriculture. Highly ripe organically-grown apples (starch degradation 9.7) were stored under different conditions and evaluated for physicochemical attributes such as fruit weight, firmness, juiciness, total soluble solids, titratable acidity, pH value and aroma profile. The analysis of primary and secondary aroma compounds was conducted utilizing HS-SPME-GCMS and the results were integrated with sensory evaluation. Crimson Crisp apples stored under controlled atmosphere with (MCP) or without (CA) application of 1-MCP, had a higher overall quality than those stored in air (RA) after a storage period of six months. The results from sensory analysis indicated that storage with temperature control alone was not suitable for preserving the distinct properties such as crispness or juiciness of Crimson Crisp apples. However, a significant increase particularly in secondary aroma compounds in RA-stored apples was found accompanied by structural disorders of the apple tissue. While a significant decline in the volatile fraction of CA and MCP-stored apples was observed, PCA showed close correlation between the CA stored and the fresh apple samples. Furthermore, these results demonstrate that the applied measures which are taken to prolong the storage time of Crimson Crisp apples, significantly impact the biochemical reactions in the fruits which are responsible for formation of flavor. These findings underscore the significance of comprehensive aroma analysis for new agricultural products and emphasize the potential for improved the quality of organic apples through carefully considered harvest and storage regimes.

Physicochemical Attributes, Volatile Profile and Sensory Quality of Organic Crimson Crisp Apples during On-Tree Maturation.

When new apple cultivars are planted, knowledge of their maturation and ripening behavior and, as a consequence, the best time for their harvest is of utmost importance for providing fruits of the highest quality to consumers. In this study, we followed the on-tree maturation and ripening behavior of organic Crimson Crisp apples over a period of almost 3 months. With the weekly analyses of basic fruit quality attributes (weight, fruit firmness, total soluble solids, titratable acids, starch degradation) in combination with the fruit volatilome (primary and secondary volatiles) and sensory analysis, we obtained a holistic picture of the maturation and ripening properties of this new variety. We could show that at the recommended harvest window, which is based on the degree of starch degradation alone, the fruit development is not finished. Synthesis of aroma volatiles-which is strongly related to the expression of pronounced fruity, apple-like flavor-requires two additional weeks of on-tree ripening. Results indicate an upregulation of 13-LOX at very early maturation stages, while upregulation of 9-LOX and enzyme systems involved in the ß-oxidation pathway requires a prolonged on-tree maturation period. The results of this study demonstrate that the analysis of basic fruit quality attributes is not sufficient for understanding the properties of apples. However, we demonstrate that the analysis of the fruit volatilome is a valuable and necessary tool for optimizing the quality of new apple varieties.

Investigating New Sensory Methods Related to Taste Sensitivity, Preferences, and Diet of Mother-Infant Pairs and Their Relationship With Body Composition and Biomarkers: Protocol for an Explorative Study.

BACKGROUND: Early experiences with different flavors play an important role in infant development, including food and taste acceptance. Flavors are already perceived in utero with the development of the taste and olfactory system and are passed on to the child through breast and bottle feeding. Therefore, the first 1000 days of life are considered a critical window for infant developmental programming. OBJECTIVE: The objective of our study is to investigate, both in the prenatal and postnatal period, taste sensitivity, preferences, and dietary diversity of mother-infant pairs. The explorative study design will also report on the impact of these variables on body composition (BC) and biomarkers. In contrast to conventional methods, this study involves long-term follow-up data collection from mother-infant pairs; moreover, the integration of audiovisual tools for recording infants' expressions pertaining to taste stimuli is a novelty of this study. Considering these new methodological approaches, the study aims to assess taste-related data in conjunction with BC parameters like fat-free mass or fat mass, biomarkers, and nutritional intake in infants and children. METHODS: Healthy pregnant women aged between 18 and 50 years (BMI≥18.5 kg/m2 to ≤30 kg/m2; <28 weeks of gestation) were recruited from January 2014 to October 2014. The explorative design implies 2 center visits during pregnancy (24-28 weeks of gestation and 32-34 weeks of gestation) and 2 center visits after delivery (6-8 weeks postpartum and 14-16 weeks postpartum) as well as follow-up visits at 1, 3-3.5, and 6 years after delivery. Data collection encompasses anthropometric and biochemical measurements as well as BC analyses with air displacement plethysmography, taste perception assessments, and multicomponent questionnaires on demographics, feeding practices, and nutritional and lifestyle behaviors. Audiovisual data from infants' reactions to sensory stimuli are collected and coded by trained staff using Baby Facial Action Coding and the Body Action Posture System. Birth outcomes and weight development are obtained from medical records, and additional qualitative data are gathered from 24 semistructured interviews. RESULTS: Our cohort represents a homogenous group of healthy women with stringent exclusion criteria. A total of 54 women met the eligibility criteria, whereas 47 mother-child pairs completed data collection at 4 center visits during and after pregnancy. Follow-up phases, data analyses, and dissemination of the findings are scheduled for the end of 2023. The study was approved by the ethics committee of the Medical University of Graz (EC No 26-066 ex 13/14), and all participants provided informed consent. CONCLUSIONS: The results of this study could be useful for elucidating the connections between maternal and infant statuses regarding diet, taste, biomarkers, and prenatal and postnatal weight development. This study may also be relevant to the establishment of further diagnostic and interventional strategies targeting childhood obesity and early body fat development. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/37279.

Comparison of volatile compounds and sensory profiles of alcoholic black currant (Ribes nigrum) beverages produced with Saccharomyces, Torulaspora, and Metschnikowia yeasts.

Black currants (Ribes nigrum) were fermented with Saccharomyces and non-Saccharomyces yeasts without added sugar to yield low-ethanol-content beverages. The effects of yeasts on the volatile compounds and sensory characteristics were analysed by HS-SPME-GC-MS, GC-O, and generic descriptive analysis. Ninety-eight volatile compounds were identified from the black currant juice and fermented beverages. Significant increases in the contents of esters (131 %), higher alcohols (391 %), and fatty acids (not present in juice sample) compared to initial juice were observed depending on the yeasts used. GC-O analysis revealed the higher impact of esters on the sensory properties of Saccharomyces bayanus-fermented beverage compared to the Torulaspora delbrueckii-fermented beverage. In the sensory evaluation, non-Saccharomyces yeasts resulted in a higher 'black currant odour'. However, all beverages were intensely sour, which can be a significant challenge in the development of alcoholic berry beverages.

The Impact of the Fermentation Strategy on the Flavour Formation of Ilzer Rose (Malus domestica Borkh.) Apple Wine.

The flavour and the volatilome of apple wines made from the Austrian heritage variety Ilzer Rose was in the scope of this study. The apple wines were produced by adopting oenological practises that are not commonly used in fruit wine production. Different fermentation strategies including the addition of enzymes with ß-glucosidase activity, addition of a fining agent, maceration of the mash along with mash fermentation were applied. The volatile compounds of the juices as intermediates and the resulting apple wines were analysed using headspace-SPME GC-MS. CATA technique with a well-trained panel was applied for sensory evaluation. The results show that the flavour of single-variety apple wine can be significantly altered by taking oenological measures. High correlations were found between the results of the analytical investigation and the sensory evaluation. Maceration of the mash leads to an increase in the fruity character of the products, also reflected by significantly higher fruit ester quantities in the wine. During mash fermentation, spontaneous malolactic fermentation was induced leading to a product with new, but thoroughly interesting sensory properties of the apple wine. The results of this study demonstrate that the integration of oenological measures may open a wide field to the development of a high diversity in apple wine flavour.

The impact of ventilation during postharvest ripening on the development of flavour compounds and sensory quality of mangoes (Mangifera indica L.) cv. Kent.

The postharvest ripening behaviour of mangoes (Mangifera indica L.) and particularly the development of colour, volatiles, sensory properties and texture, were investigated. Mangoes cv. Kent from Peru were arranged in a postharvest ripening chamber in two different ways enabling different ventilation of the fruits. Fruit properties were investigated in comparison to reference fruits after postharvest ripening for 78 h. Volatile compounds were analysed by HS-SPME GC-MS; an expert panel performed sensory analysis using descriptive methods. The arrangement of the mangoes significantly impacted the ripening procedures. Dense fruit arrangement induced a degradation of terpenes, a reduced formation of reaction products from the lipoxygenase pathway and less pronounced fruitiness and mango flavour. Principal component analysis based on volatile compounds and sensory properties showed a high correlation with the position in the ripening chamber. These data demonstrate the urgent need for further investigations of the postharvest ripening processes to increase mango quality.

"More than Honey": Investigation on Volatiles from Monovarietal Honeys Using New Analytical and Sensory Approaches.

Eight monovarietal honeys from dandelion, fir tree, linden tree, chestnut tree, robinia, orange, lavender, and rape were investigated with respect to their volatile compounds and sensory properties. Analysis of the volatile compounds was performed by gas chromatographic techniques (one-dimensional GC-MS as well as comprehensive GC×GC-MS). For sensory evaluation Napping in combination with ultraflash profiling was applied using sensory experts. For dandelion honey, 34 volatile compounds are described for the first time to be present in dandelion honey. PCA and cluster analysis of the volatile compounds, respectively, show high correlation with the PCA obtained from sensory evaluation. Lavender and linden honey showed sensory characteristics that were not expected from these honey types. Analysis of the volatile compounds resulted in the identification of odor-active compounds that are very likely derived from sources other than the respective honeyflow. Contamination with essential oils used in apiculture is very likely to be the reason for the occurrence of these compounds in the investigated honeys.

Determination of sulfur and nitrogen compounds during the processing of dry fermented sausages and their relation to amino acid generation.

The identification of odor-active sulfur and nitrogen compounds formed during the processing of dry fermented sausages was the objective of this study. In order to elucidate their possible origin, free amino acids (FAAs) were also determined. The volatile compounds present in the dry sausages were extracted using solvent assisted flavor evaporation (SAFE) and monitored by one and two-dimensional gas chromatography with different detectors: mass spectrometry (MS), nitrogen phosphorous (NPD), flame photometric (FPD) detectors, as well as gas chromatography-olfactometry. A total of seventeen sulfur and nitrogen compounds were identified and quantified. Among them, 2-acetyl-1-pyrroline was the most potent odor active compound, followed by methional, ethylpyrazine and 2,3-dihydrothiophene characterized by toasted, cooked potato, and nutty notes. The degradation of FAAs, generated during processing, was related to the production of aroma compounds, such as methionine forming methional and benzothiazole while ornithine was the precursor compound for 2-acetyl-1-pyrroline and glycine for ethylpyrazine.

Study of the influence of maceration time and oenological practices on the aroma profile of Vranec wines.

Vranec is one of the most important red grape varieties in Republic of Macedonia, grown in all vineyards, mostly in the Tikves wine region. In this study, Vranec wines produced with different maceration times (4, 7, 14 and 30 days) in presence of enzyme and oak chips during fermentation were studied in order to determine the influence of vinification conditions on the aroma profile. The volatile compounds were determined using headspace solid phase microextraction (HS-SPME) with a PDMS/Carboxen/DVB fibre, coupled with gas chromatography-mass spectrometry (GC-MS). In total 63 aroma compounds were detected revealing a complex aroma profile of Vranec wines composed of esters, alcohols, fatty acids, aldehydes, ketones and sulphur compounds. The content of aroma compounds was related mostly to maceration time, observing increased relative amount of alcohols, esters and fatty acids from the fourth to seventh day of maceration and the presence of oak chips during the fermentation enhanced their formation. The Student-Newman-Keuls test has been applied to ascertain possible significant differences between the studied wines, and principal component analysis has been employed, showing separation and grouping of the wines according to maceration time and oak chips treatment.

Monitoring the plant epiphyte Methylobacterium extorquens DSM 21961 by real-time PCR and its influence on the strawberry flavor.

Besides its influence on plant growth and health, plant-associated bacteria exert an impact on fruit quality. Methylotrophic bacteria can enhance the biosynthesis of strawberry flavor compounds, especially the two furanoid compounds 2,5-dimethyl-4-hydroxy-2H-furanone (DMHF) and 2,5-dimethyl-4-methoxy-2H-furanone in vitro. Here, we report the selection and characterization of Methylobacterium extorquens DSM 21961, a strain that was able to enhance the furanone content ad planta under greenhouse conditions. For monitoring the colonization of strawberry plants, a strain-specific quantification system for M. extorquens DSM 21961 was developed. Specificity, linear range and quantitative limit of the system were shown, and successful application was demonstrated in a monitoring experiment of M. extorquens DSM 21961 on strawberry leaves under greenhouse conditions. Furthermore, the quantification of DMHF in strawberry fruits via GC indicated an increased biosynthesis of this compound in strawberry plants. The colonization behavior analyzed by confocal laser scanning microscopy using GFP-tagged cells revealed high colonization of the upper and the lower leaf surfaces, with a specific accumulation of bacterial cells on trichomes. The results support a biotechnological application of this promising flavor-stimulating agent.

Growth behavior of off-flavor-forming microorganisms in apple juice.

Alicyclobacillus acidoterrestris and Streptomyces griseus griseus are two bacteria species that are frequently found in apple juice as spoilage bacteria. They both show thermoacidophilic behavior, adapting to the low pH of the juices and being able to survive high temperatures. They are able to regerminate in the shelf-stable product and spoil the juice by the formation of off-flavor compounds (i.e., guaiacol and 2,6-dibromophenol as metabolites of A. acidoterrestris and 2-isopropyl-3-methoxypyrazine, 2-methylisoborneol, 2-isobutyl-3-methoxypyrazine, and geosmin as important metabolites of S. griseus). In this study the growth behavior of the strains and the impact on apple juice were investigated under different conditions (i.e., temperature, oxygen supply, and mutual influence of the strains). The off-flavor formation was monitored by GC-MS after headspace SPME and subsequent calculation of the odor activity values. The results showed that S. griseus grows and consequently spoils the product even at 4 degrees C, whereas A. acidoterrestris needs at least room temperature to show significant growth. Limited oxygen supply did not significantly reduce off-flavor formation for any of the strains. The simultaneous presence of the strains in the juice reduced the growth of both species; nevertheless, off-flavor was detected.

Odor thresholds of microbially induced off-flavor compounds in apple juice.

Microbially derived off-flavor is a major problem in apple juice production as it diminishes the sensory quality of the juice significantly. Fifteen relevant off-flavor compounds that are formed in apple juice, for example, by the strains Alicyclobacillus acidoterrestris and Actinomycetes (Streptomyces ssp.) were investigated with respect to their sensory relevance. The odor threshold values (i.e., detection and recognition values) were determined for all compounds in the matrix apple juice. Odor threshold values for fenchyl alcohol are reported here for the first time. The obtained values were set in relation to the limits of detection and quantification of a previously published GC-MS method. Eight tainted apple juice samples were analyzed for the presence of the 2 strains and the 15 off-flavor compounds. Both strains could be found in the samples; the presence of Streptomyces ssp. as spoilage bacteria of apple juice is reported for the first time. In samples with distinct off-flavor, 2-isopropyl-3-methoxypyrazine, 2-isobutyl-3-methoxypyrazine, 2-methylisoborneol, 1-octen-3-ol, fenchyl alcohol, geosmin, and guaiacol as well as 2,6-dibromophenol were determined in concentrations higher than the detection threshold.

Sensitive method for the determination of nitrated polycyclic aromatic hydrocarbons in the human diet.

The presence of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) as contaminants in foods is nowadays a legitimate cause of concern, as they are reported to be strong direct-acting mutagens and carcinogens that may pose a risk to human health. Nevertheless, their concentrations in foods are in the ultra-trace region. In this study, we present a very sensitive analytical method for the determination of this compound class in complex food matrices. Special emphasis was put on sample extraction and clean up. Recoveries of 75% could be obtained for 1- and 2-nitronaphthalene; for all other compounds investigated the recoveries were >/=94%. The determination of the compounds was performed by gas chromatography-mass spectrometry. The results show that the use of negative chemical ionization (NCI) increases the sensitivity by one order of magnitude in comparison to electron impact ionization (EI) (limits of detection 0.07-0.25 micro g kg(-1) for EI and 0.01-0.02 micro g kg(-1) for NCI). The influence of the sample matrix on the sensitivity of the method is demonstrated with extracts of a sample from a duplicate diet study. Due to the lack of a certified reference material the suitability of the method is demonstrated with pumpkin seed oil that was spiked with nitro-PAHs at two different concentration levels.