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Black pepper is a commercially important commodity, which is susceptible for fraudulent additions. Analytical tools are capable of detection of specific additions, but in most published cases these tools and associated mathematical models are suitable for only one or a few predetermined adulterants. There is a need for methodology that can detect any addition without having to know the type of adulterant a priori. We analysed a dataset of 200 authentic black pepper samples and a total of 210 adulterated samples consisting of mixtures of black pepper and oil-dress pepper, spent pepper, coffee husk, coffee skin and papaya seeds, respectively. A small, non-destructive spectral tool, a visible-near infrared spectrophotometer, (VIS/NIR) and a slower and more expensive mass spectrometric tool, direct analysis in real time-mass spectrometer (DART-MS), were evaluated according to their performances in terms of adulteration detection for a number of machine learning modes. The often-used approach where an ‘optimal’ model is selected and employed yielded for VIS/NIR very reasonable results for most of the adulterants used, but no single model performed well for all adulterants in the dataset. However, high-level fusion modelling of both one- and two-class models developed for different adulterant types using a penalized excess scoring system led to a performance of typically >75% correct classification, regardless of the nature of the adulterant. DART-MS outperformed VIS/NIR but also led to no single model that was able to detect all adulterants present. From the small number of tested fusion strategies, again the penalized excess score outperformed the other fusion options and yielded perfect classification scores for all but one of the adulterants tested. This shows that this type of modelling for cases where the nature of a target is unknown is a promising approach. It is even speculated that this modelling approach is likely to be suitable for types of adulterant that were not used in the model development phase.

Background Current developments in portable photonic devices for fast authentication of extra virgin olive oil (EVOO) or EVOO with non-EVOO additions steer towards hyphenation of different optic technologies. The multiple spectra or so-called “fingerprints” of samples are then analyzed with multivariate statistics. For EVOO authentication, one-class classification (OCC) to identify “out-of-class” EVOO samples in combination with data-fusion is applicable. Objective Prospecting the application of a prototype photonic device (“PhasmaFood”) which hyphenates visible, fluorescence, and near-infrared spectroscopy in combination with OCC modelling to classify EVOOs and discriminate them from other edible oils and adulterated EVOOs. Method EVOOs were adulterated by mixing in 10–50% (v/v) of refined and virgin olive oils, olive-pomace olive oils, and other common edible oils. Samples were analyzed by the hyphenated sensor. OCC, data-fusion, and decision thresholds were applied and optimized for two different scenarios. Results By high-level data-fusion of the classification results from the three spectral databases and several multivariate model vectors, a 100% correct classification of all pure edible oils using OCC in the first scenario was found. Reducing samples being falsely classified as EVOOs in a second scenario, 97% of EVOOs adulterated with non-EVOO olive oils were correctly identified and ones with other edible oils correctly classified at score of 91%. Conclusions Photonic sensor hyphenation in combination with high-level data fusion, OCC, and tuned decision thresholds delivers significantly better screening results for EVOO compared to individual sensor results. Highlights Hyphenated photonics and its data handling solutions applied to extra virgin olive oil authenticity testing was found to be promising.

The aim of the present article was an in-depth characterization of cyanidine-rich red cabbage extracts and the identification of challenges emerging during the purification of their pigments. Two extraction procedures using either hot acidified or temperate water at its genuine pH were compared. LC-MS analyses revealed 20 mostly acylated anthocyanins, five aliphatic glucosinolates, and four indolic glucosinolates as non-volatile constituents. In addition, volatiles were characterized by HS-SPME-GC-MS. Whereas the glycosidic precursors do not impair the sensory properties, their enzymatic degradation products may evoke unpleasant flavors. The crude pigment extract obtained with hot acidified water contained low concentrations of C6 aldehydes, isothiocyanates, nitriles, and sulfides, and was selected for purification experiments. Amberlite XAD 16 HP, polyamide, chitosan, and lignosulfonate were used as adsorbents and flocculants. Particularly, Amberlite and lignosulfonate treatment diminished the content of glucosinolates and volatiles. Interestingly, indolic glucosinolates and acylated anthocyanins showed similar behavior in all purification procedures performed.

The detection of fraudulent additions to milk powder is an ongoing research subject for governmental agencies, industry and academia. Current developments steer towards the application of so-called fingerprint approaches, describing authentic, reference samples with spectroscopy and using one-class classification (OCC) to identify “out-of-class”, or adulterated samples. Within this article we describe the application of a novel, portable device hyphenating ultraviolet–visible, fluorescence and near-infrared spectroscopy in combination with OCC modelling to discriminate authentic skimmed milk powders from adulterated ones. As adulterated samples we analyzed skimmed milk powder with the addition of plant protein powder, whey powder, starch, lactose, glucose, fructose as well as non-protein nitrogen like ammonium chloride, ammonium nitrate, melamine and urea in different concentrations. After fusion of the classification results from the three spectral techniques and several models two scenarios are presented. 100% (scenario 1) or 80% (scenario 2) of the authentic skimmed milk powders were correctly identified as “in-class”, whereas respectively 64% or 86% of the adulterated samples were correctly classified as “out-of-class”. In brief, this article provides insights in the application of novel, portable devices that may be applied in a non-invasive manner and gives an outlook on data handling and a new data fusion strategy.

Background Optical technologies, relying on spectral analysis, are more and more implemented in portable devices for food analysis. Thereby, each food safety, quality or authenticity provision as well as each technology requires the generation of a dedicated spectral database with reference data. Currently, knowledge on how these databases might be connected or transferred across food commodities, targeted compounds or devices are very limited. Hence, repetitive work is conducted and technologies are not optimally used. Scope and approach This perspective focuses on the currently available technologies and approaches for data handling and database transfer across miniaturized devices and technologies for food safety, quality and authenticity assessments. Key findings and conclusions For almost every food commodity or target compound a miniaturized spectroscopic device can be applied with the respective database to compare findings. Recent developments in optical spectroscopy allow more possibilities for their use as well as facilitate the production of portable devices. A multifunctional device hyphenating several sensors and broadening the application range is still not marketed. Newly developed software architecture, accessing and extracting data, helps to overcome sample heterogenicity or spurious measured data. In addition, several data fusion approaches using machine learning and deep learning strategies are available to fuse spectroscopic data with itself or other non-spectroscopic data. Following the research results presented in this field, spectral data can possibly be re-used and shared across instruments and locations, highly increasing the applicability of data sets. Thereby, obstacles such as policy or confidentiality are taken into account.

Purpose The purpose of this paper is to provide insight into the consumers’ perception of natural and artificial food colourants. Furthermore, attitudes towards the application of carmine, being technically important and ubiquitously used to impart red shades, are assessed and analysed. Originating from insects, carmine is considered as natural but may arouse disgust. Design/methodology/approach In total, 625 individuals were surveyed using an online, self-administered questionnaire to represent a broad cross-section of the German population. Findings Independent of their origin, the application of colourants was rejected by 57.0 per cent of the interviewees. In total, 31.8 per cent of the participants stated a neutral attitude, while only 11.2 per cent expressed a positive notion. Most respondents preferred colourants from natural sources to artificial ones. While consumers perceive natural food colourants composed of genuine plant pigments positively, 61.6 per cent of respondents disliked the application of animal-derived colourants, 24.8 per cent of them did neither reject nor like it, and only 13.6 per cent of the interviewees stated a positive attitude towards them. The findings of this paper further indicate consumers’ preference for colourants to be either artificial or plant-derived rather than carmine. Food colourants are being rejected, possibly due to misleading information and confusing labelling. Consequently, information about carmine, including its origin and production, did not increase the aversion to products that are dyed with it, but increased their acceptance. Originality/value This study outlines consumer perception and attitudes towards food colourants. For the first time, the findings of this paper report the effect of revealing information about an additive, which initially aroused disgust, and its influence on consumer perception.

A wide range of natural food colorants and coloring foodstuffs is available for the food industry to meet current costumer trends. Most natural pigments are more sensitive towards heat, light, and pH changes compared to their synthetic counterparts. Additionally, high dosages are often required to attain desired color hues and intensities. In this research article, we report on the broad and worldwide incidence of a fraudulent practice to overcome these disadvantages by adding a non-approved azo-dye preparation originating from the textile dye Reactive Red 195 to natural pigment extracts. Since the respective products and their derivatives have been widely distributed, we present a rapid method allowing the differentiation of the fraudulent azo-dye from Hibiscus sabdariffa (roselle) flower and Beta vulgaris (red beet) root extracts, the two coloring foodstuffs that are most frequently adulterated. Furthermore, detailed HPLC-PDA-MS/MS data is presented for the unambiguous identification of Reactive Red 195 and its derivatives.

Pelargonidin-based colors suffer from notorious instability. A phenolic mango peel extract and defined phenolic fractions thereof were shown to effectively modulate the visible absorption of anthocyanins from strawberry (Fragaria x ananassa Duch.) and red radish (Raphanus sativus L.) by intermolecular co-pigmentation. Consistently, non-acylated pelargonidin derivatives from strawberry exerted significantly greater hyper- and bathochromic spectral shifts than their acylated counterparts from red radish. The addition of low molecular-weight co-pigments such as gallic acid and monogalloyl glucoses to strawberry anthocyanins led to strong hyperchromic shifts from 30% to 48%, while gallotannins (>six galloyl units) exerted smaller co-pigmentation effects (36±2%; Δλmax 13nm), possibly due to steric hindrances. In contrast, penta- and hexa-O-galloyl-glucose induced greatest and most stable co-pigmentation effects (53±2%; Δλmax 13nm). Irrespective of the underlying mechanisms and the responsible compounds, phenolic mango peel extracts might represent suitable color enhancers for coloring foodstuff, particularly for those containing non-acylated pelargonidin derivatives.

Food producers thrive towards the satisfaction of today’s consumer demands for natural, safe, and sustainable food products. Thereby, the application of food colorants is a major issue. In this article, we aimed at giving insights into the evaluation of natural and artificial food colorants and revealing weaknesses within the value chain by use of a hot spot analysis. Implying red hues, natural plant-based anthocyanins (E163) and lycopene (E160d), natural animal-derived carmine (E120), and chemically synthesized Allura Red AC (E129) were chosen to cover a wide range of value chains. Three major metrics were identified - environment, economics including legal aspects, and social responsibility. The first two metrics considered topics related to food producers and food additive manufacturers. Animal husbandry and crop cultivation, yield of the raw material, environmentally friendly production, exploitation of by-products, and naturalness were indicators for the environment metric. The economic metric consisted of the additives’ convenience for application, price, sensory properties, shelf life, restriction as limited application and legal labeling, stability within the food matrix, and availability. In contrast, the metric social responsibility combined all topics important to consumers and workers such as health promoting or harming ingredients, consumers’ attitudes towards the additives, as well as working conditions during production. Applying the indicators to four different food colorants all imparting the same color hue, the natural, plant-derived colorant anthocyanins (E163) was found to be more sustainable than the natural, animal-derived colorant carmine (E120), the natural, plant-derived colorant lycopene (E160d), and the artificial colorant Allura Red AC (E129).

The knowledge of pectin esterification degree is of primary importance to predict gelling and other properties of pectin from different sources. This paper reports the development of a simple and rapid 1H NMR-based method for the simultaneous quantitative determination of methylation, acetylation, and feruloylation degree of pectin isolated from various food sources. Pectin esters are hydrolyzed in NaOH/D2O, and the obtained methanol, acetic acid, and ferulic acid are directly measured by 1H NMR. High accuracy, repeatability, and reproducibility of the method were obtained, and the analysis time is reduced as compared to conventional chromatography- or titration-based methods.

Using a simulated digestion procedure in vitro, liberation and bioaccessibility of β-carotene (29.5±1.7% and 22.6±0.9%, respectively) and lycopene (51.3±2.6% and 33.2±3.1%, respectively) from gac fruit aril were found to be significantly higher than from carrot root (β-carotene, 5.2±0.5% and 0.5±0.2%, respectively) and tomato fruit (lycopene, 15.9±2.8% and 1.8±0.5%, respectively). Gac fruit aril naturally contained significantly more lipids (11% on fresh weight base) than carrot root and tomato fruit (

Since ancient times, cochineal, obtained from the aphid Dactylopius coccus COSTA, has been used for coloring food. The insect is native to subtropical and tropical areas, parasitically living on Opuntia ficus-indica (L.) Mill. cacti. Main cochineal production is conducted in Peru, Bolivia, Argentina, and the Canary Islands. Related products are the anthraquinone carminic acid and its aluminum complex carmine. These colorants are permitted as food ingredients in most countries. Benefits of carmine are its excellent heat and light stability, but its nauseating animal origin, its aluminum content, microbiological issues, and its ability for inducing severe allergic reactions led to several public scandals. Consequently, pigments of synthetic or plant origin have most recently been applied as potential substitutes in the food industry. This chapter will provide insights about production, chemistry, legal requirements, applications, and diverse issues related with this colorant, furthermore providing an overview of possible substitutes.

The knowledge of pectin esterification degree is of primary importance to predict gelling and other properties of pectin from different sources. This paper reports the development of a simple and rapid (1)H NMR-based method for the simultaneous quantitative determination of methylation, acetylation, and feruloylation degree of pectin isolated from various food sources. Pectin esters are hydrolyzed in NaOH/D2O, and the obtained methanol, acetic acid, and ferulic acid are directly measured by (1)H NMR. High accuracy, repeatability, and reproducibility of the method were obtained, and the analysis time is reduced as compared to conventional chromatography- or titration-based methods.

In the present paper, 26 food waste streams were selected according to their exploitation potential and investigated in terms of pectin content. The isolated pectin, subdivided into calcium bound and alkaline extractable pectin, was fully characterized in terms of uronic acid and other sugar composition, methylation and acetylation degree. It was shown that many waste streams can be a valuable source of pectin, but also that pectin structures present a huge structural diversity, resulting in a broad range of pectin structures. These can have different physicochemical and biological properties, which are useful in a wide range of applications. Even if the data could not cover all the possible batch by batch and country variabilities, to date this represents the most complete pectin characterization from food waste streams ever reported in the literature with a homogeneous methodology.