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23. Using a Machine Learning Regression Approach to Predict the Aroma Partitioning in Dairy Matrices †.

Author

Anker, Marvin, Borsum, Christine, Zhang, Youfeng, Zhang, Yanyan, and Krupitzer, Christian

Subjects
FOOD aroma, ARTIFICIAL neural networks, MACHINE learning, REGRESSION analysis, SPECIFIC gravity, DATA scrubbing
Abstract

Aroma partitioning in food is a challenging area of research due to the contribution of several physical and chemical factors that affect the binding and release of aroma in food matrices. The partition coefficient measured by the K m g value refers to the partition coefficient that describes how aroma compounds distribute themselves between matrices and a gas phase, such as between different components of a food matrix and air. This study introduces a regression approach to predict the K m g value of aroma compounds of a wide range of physicochemical properties in dairy matrices representing products of different compositions and/or processing. The approach consists of data cleaning, grouping based on the temperature of K m g analysis, pre-processing (log transformation and normalization), and, finally, the development and evaluation of prediction models with regression methods. We compared regression analysis with linear regression (LR) to five machine-learning-based regression algorithms: Random Forest Regressor (RFR), Gradient Boosting Regression (GBR), Extreme Gradient Boosting (XGBoost, XGB), Support Vector Regression (SVR), and Artificial Neural Network Regression (NNR). Explainable AI (XAI) was used to calculate feature importance and therefore identify the features that mainly contribute to the prediction. The top three features that were identified are log P, specific gravity, and molecular weight. For the prediction of the K m g in dairy matrices, R 2 scores of up to 0.99 were reached. For 37.0 ° C, which resembles the temperature of the mouth, RFR delivered the best results, and, at lower temperatures of 7.0 ° C, typical for a household fridge, XGB performed best. The results from the models work as a proof of concept and show the applicability of a data-driven approach with machine learning to predict the K m g value of aroma compounds in different dairy matrices. [ABSTRACT FROM AUTHOR]

Published
2024
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34. Characterization of the aroma properties in fragrant rapeseed oil and aroma variation during critical roasting phase

Author

Zhang, Youfeng and Zhang, Youfeng

Abstract

Rapeseed oil is one of the third most-produced vegetable oil in the world, which is appreciated for its characteristic flavor and high nutritional value. Fragrant rapeseed oil (FRO) produced by a typical roasting process is popular for its characteristic aroma, which has an annual consumption exceeding 1.5 million tons. However, the changes in aroma blueprint of FRO during the typical roasting processing are still unclear, which challenges rapeseed oil quality and consumer acceptance. Accordingly, the aim of this work was to investigate the aroma characteristics and their precursors pyrolysis behavior of FRO to provide a basis and guidance for the control of FRO aroma quality during production processing. First, a systematic review on summarizing, comparing, and critiquing the literature regarding the flavor of rapeseed oil, especially about employed analysis techniques (i.e., extraction, qualitative, quantitative, sensorial, and chemometric methods), identified representative/off-flavor compounds, and effects of different treatments during the processes (dehulling, roasting, microwave, flavoring with herbs, refining, oil heating, and storage) was performed. One hundred and thirty-seven odorants found in rapeseed oil from literature are listed, including aldehydes, ketones, acids, esters, alcohols, phenols, pyrazines, furans, pyrrolines, indoles, pyridines, thiazoles, thiophenes, further S-containing compounds, nitriles, and alkenes, and possible formation pathways of some key aroma-active compounds are also proposed. Nevertheless, some of these compounds require further validation (e.g., nitriles) due to lack of recombination experiments in the previous work. To wrap up, advanced flavor analysis techniques should be evolved toward time-saving, portability, real-time monitoring, and visualization, which aims to obtain a “complete” flavor profile of rapeseed oil. Aparting from that, studies to elucidate the influence of key roasting processing on the formation of aro, Rapsöl ist eines der am dritthäufigsten produzierten Pflanzenöle der Welt, welches für seinen charakteristischen Geschmack und hohen Nährwert geschätzt wird. Geröstetes Rapsöl (fragrant rapeseed oil, FRO), das durch ein typisches Röstverfahren hergestellt wird, ist wegen seines charakteristischen Aromas beliebt und jährlich werden mehr als 1,5 Millionen Tonnen produziert. Allerdings sind die Veränderungen im Aromaprofil von FRO während der typischen Röstverarbeitung noch unklar, was die Rapsölqualität und die Verbraucherakzeptanz herausfordert. Dementsprechend war das Ziel dieser Arbeit, die Aromaeigenschaften und das Pyrolyseverhalten der Vorläuferverbindungen von FRO zu untersuchen, um eine Grundlage und Anleitung für die Kontrolle der FRO-Aromaqualität während des Herstellungsprozesses zu liefern. Zuerst wurde eine systematische Übersicht aus der Literatur über die Zusammenfassung, den Vergleich und die Kritik zum Aroma von Rapsöl, insbesondere zu den verwendeten Analysetechniken (d. h. Extraktion, qualitative, quantitative, sensorische und chemometrische Methoden), identifizierte repräsentative Verbindungen und Fehlaromen, und Auswirkungen verschiedener Prozesse während der Herstellung (Schälen, Rösten, Mikrowellenbehandlung, Aromatisierung mit Kräutern, Raffination, Ölerhitzung und Lagerung) durchgeführt. Einhundertsiebenunddreißig in Rapsöl beschriebene Aromastoffe sind aufgelistet, darunter Aldehyde, Ketone, Säuren, Ester, Alkohole, Phenole, Pyrazine, Furane, Pyrroline, Indole, Pyridine, Thiazole, Thiophene, weitere S-haltige Verbindungen, Nitrile und Alkene. Die mögliche Bildungswege einiger wichtiger aromaaktiver Verbindungen werden ebenfalls vorgeschlagen. Dennoch erfordern einige dieser Verbindungen eine weitere Validierung (z. B. Nitrile) aufgrund fehlender Rekombinationsexperimente in den vorherigen Arbeiten. Abschließend sollten fortschrittliche Aromaanalysetechniken in Richtung Zeitersparnis, Übertragung, Echtzeitüberwachung und Visualisierung weitere

Published
2023

41. Sensory analysis, aroma compounds and flavour modulation of rapeseed oil: A review

Author

Zhang, Youfeng, Wu, Yuqi, Chen, Sirui, Yang, Binbin, Zhang, Hui, Wang, Xingguo, Granvolg, Michael, and Jin, Qingzhe

Subjects
aroma compound, flavour modulation, rapeseed oil, flavour, sensory analysis
Abstract

Rapeseed oil, one of the world’s three major vegetable oils, is appreciated for its characteristic flavour and high nutritional value. Flavor is an important determinant of oil quality and consumer acceptance. This review systematically evaluates and discusses recent advances and knowledge on the sensory analysis and aroma compounds of rapeseed oil. One hundred and ninety-nine aroma compounds in rapeseed oil were found in literature. They mainly contribute to the roasty, fatty, cheese-like, green, fruity, pungent, sweaty, sweet, spicy, flowery, nutty, earthy, and sulphury flavour. Among them, one hundred and fourteen substances have been reported to be odorants in rapeseed oil only once before in the literature, which require further validation via aroma reconstitution and omission test. The processes (storage, dehulling, thermal treatment, flavouring with herbs, and refining) affecting the flavour of rapeseed oil from sensory and molecule perspectives were also summarized. Studies to elucidate the formation mechanisms of aroma compounds in rapeseed oil by different processes are needed, which will contribute to get a deeper understanding of factors leading to the variations of flavour and to produce rapeseed oil products with a desired aroma and a higher consumer acceptance.

Published
2022
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42. Upcycling of Soy Whey with Ischnoderma benzoinumtoward Production of Bioflavors and Mycoprotein

Author

Liang, Jiaqi, Xu, Ning, Nedele, Ann-Kathrin, Rigling, Marina, Zhu, Lin, Zhang, Youfeng, Stöppelmann, Felix, Hannemann, Lea, Heimbach, Julia, Kohlus, Reinhard, and Zhang, Yanyan

Abstract

Soy whey is becoming a worldwide issue as a liquid waste stream that is often discarded after tofu, soy protein, and soy-based dairy alternative manufacturing. This study established a model to produce a bioflavor and mycoprotein using fermentation of soy whey by a basidiomycete Ischnoderma benzoinum. Under the dedicated control of a fermentation system, an intense almond-like and sweetish aroma was perceived by a trained sensory panel (n= 10) after fermentation of pure soy whey within 20 h. By application of direct immersion–stir bar sorptive extraction combined with gas chromatography–mass spectrometry–olfactometry (DI-SBSE-GC–MS–O), around 1.0 mg/L benzaldehyde and 1.1 mg/L 4-methoxybenzaldehyde imparting a pleasant almond-like odor note were determined in the fermented soy whey with I. benzoinum. Concurrently, a certain of amount of the dry mass of I. benzoinumwas accumulated with 73.2 mg/g crude protein and seven essential amino acids.

Published
2023
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49. Comparative analysis of aroma compounds in French fries and palm oil at three crucial stages by GC/MS‐olfactometry, odor activity values, and aroma recombination.

Author

Xu, Lirong, Chang, Jiarui, Mei, Xue, Zhang, Youfeng, Wu, Gangcheng, Jin, Qingzhe, and Wang, Xingguo

Subjects
OCTANOIC acid, FRENCH fries, FLAVOR, COMPARATIVE studies, CHEMICAL industry, BENZALDEHYDE
Abstract

BACKGROUND Flavor is a key element affecting the popularity of French fries (FFs). When oil is heated, the changes in oil quality can affect the flavor of the food directly. RESULTS: The flavor of FFs showed three crucial stages: the break‐in (3.0% to 6.8% of total polar compounds (TPC)), optimum (7.0% to 19% of TPC), and degrading (above 19.5% of TPC) stages. To distinguish the key aroma compounds in the three stages, the FFs, prepared in palm oil (PO) at TPC of 3.0% (FF3), 7.5% (FF8), 19.5% (FF20), and their relevant oils (PO3, PO8, PO20), were selected for molecular sensory science analysis. The results indicated that the concentration of (E, E)‐2,4‐decadienal linked with the deep‐fried odor was low in FF3, which led to a lower sensory score in the FF3 sample. The FF8 sample had a high (E, E)‐2,4‐decadienal content and received a high sensory score. The FF20 sample possessed high hexanoic acid, heptanoic acid (sweaty odor), benzaldehyde (stale odor), octanoic acid (sweaty odor), (E)‐2‐undecenal (fatty odor), and trans‐4,5‐epoxy‐(E)‐2‐decenal (metallic odor) content, thus leading to FFs having an undesirable flavor and PO20 showed high hexanoic acid and heptanoic acid content, contributing to a lower sensory score in PO20. CONCLUSION: The FFs' flavor became undesirable when TPC was above 19.5% due to significant influences of some off‐flavor compounds. It is therefore essential to prevent the generation of rancid substances to prolong the optimum stage during frying. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Published
2022
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