Consumer acceptance of microalgae as a novel food - Where are we now? And how to get further.

Microalgae provide a potential new food resource for sustainable human nutrition. Many microalgae species can produce a high content of total protein with a balanced composition of essential amino acids, healthy oils rich in polyunsaturated fatty acids, carotenoids, fibers, and vitamins. These components can be made available via unprocessed microalgae or refined as individual ingredients. In either case, if added to foods, microalgae may affect taste, smell, texture, and appearance. This review focuses on how consumer acceptance of new foods - such as microalgae - can be accessed in the world of sensory science by bringing together examples from recent consumer surveys. The main aim is to obtain an overview of the attitude towards microalgae as a food ingredient in Europe. The overarching finding suggests that European consumers generally find microalgae acceptable as ingredients in food products. However, there is a prevailing preference for keeping inclusion levels low, primarily attributed to the vivid green color that algae impart to food items upon addition. Additionally, consumers tend to favor the taste of freshwater algae over marine species, often finding the latter's pronounced fishy flavor less appealing.

Reproducibility of cerebral blood flow, oxygen metabolism, and lactate and N-acetyl-aspartate concentrations measured using magnetic resonance imaging and spectroscopy.

In humans, resting cerebral perfusion, oxygen consumption and energy metabolism demonstrate large intersubject variation regardless of methodology. Whether a similar large variation is also present longitudinally in individual subjects is much less studied, but knowing the time variance in reproducibility is important when designing and interpreting longitudinal follow-up studies examining brain physiology. Therefore, we examined the reproducibility of cerebral blood flow (CBF), global cerebral metabolic rate of oxygen (CMRO2), global arteriovenous oxygen saturation difference (A-V.O2), and cerebral lactate and N-acetyl-aspartate (NAA) concentrations measured using magnetic resonance imaging (MRI) and spectroscopy (MRS) techniques through repeated measurements at 6 h, 24 h, 7 days and several weeks after initial baseline measurements in young healthy adults (N = 26, 13 females, age range 18-35 years). Using this setup, we calculated the correlation, limit of agreement (LoA) and within-subject coefficient of variation (CoVWS) between baseline values and the subsequent repeated measurements to examine the longitudinal variation in individual cerebral physiology. CBF and CMRO2 correlated significantly between baseline and all subsequent measurements. The strength of the correlations (R2) and reproducibility metrics (LoA and CoVWS) demonstrated the best reproducibility for the within-day measurements and generally declined with longer time between measurements. Cerebral lactate and NAA concentrations also correlated significantly for all measurements, except between baseline and the 7-day measurement for lactate. Similar to CBF and CMRO2, lactate and NAA demonstrated the best reproducibility for within-day repeated measurements. The gradual decline in reproducibility over time should be considered when designing and interpreting studies on brain physiology, for example, in the evaluation of treatment efficacy.

Social learning and the adaptiveness of expressing and perceiving fearfulness.

The fearful ape hypothesis revolves around our ability to express and perceive fearfulness. Here, we address these abilities from a social learning perspective which casts fearfulness in a slightly different light. Our commentary argues that any theory that characterizes a (human) social signal as being adaptive, needs to address the role of social learning as an alternative candidate explanation.

On the social nature of abstraction: cognitive implications of interaction and diversity.

The human capacity for abstraction is remarkable. We effortlessly form abstract representations from varied experiences, generalizing and flexibly transferring experiences and knowledge between contexts, which can facilitate reasoning, problem solving and learning across many domains. The cognitive process of abstraction, however, is often portrayed and investigated as an individual process. This paper addresses how cognitive processes of abstraction-together with other aspects of human reasoning and problem solving-are fundamentally shaped and modulated by online social interaction. Starting from a general distinction between convergent thinking, divergent thinking and processes of abstraction, we address how social interaction shapes information processing differently depending on cognitive demands, social coordination and task ecologies. In particular, we suggest that processes of abstraction are facilitated by the interactive sharing and integration of varied individual experiences. To this end, we also discuss how the dynamics of group interactions vary as a function of group composition; that is, in terms of the similarity and diversity between the group members. We conclude by outlining the role of cognitive diversity in interactive processes and consider the importance of group diversity in processes of abstraction. This article is part of the theme issue 'Concepts in interaction: social engagement and inner experiences'.

Two Statistical Tools for Assessing Functionality and Protein Characteristics of Different Fava Bean (Vicia faba L.) Ingredients.

Fava bean (Vicia faba L.) is a promising source of proteins that can be potentially used as nutritional and/or functional agents for industrial food applications. Fava ingredients are industrially produced, modified, and utilized for food applications. Their processing conditions influence physico-chemical protein properties that further impact ingredient functionality. To design a functionally suitable ingredient, an understanding of the interrelationships between different properties is essential. Hence, this work aimed to assess two statistical analytical tools, Pearson's correlation and Principal Component Analysis (PCA), for investigating the role of the process conditions of fava ingredients on their functional and protein properties. Fava concentrates were processed by pH (2, 4, 6.4 and 11), temperature (55, 75 and 95 ∘C) and treatment duration (30 and 360 min) into different modified ingredients. These were utilized under two application conditions (pH 4 and 7), and their foam and emulsion properties as well as their ingredient characteristics (charge, solubility, and intrinsic fluorescence) were measured. The results show that foam and emulsion properties are not correlated to each other. They are associated with different protein and non-protein attributes as fava concentrate is a multi-component matrix. Importantly, it is found that the results from the two statistical tools are not fully comparable but do complement each other. This highlights that both statistical analytical tools are equally important for a comprehensive understanding of the impact of process conditions on different properties and the interrelationships between them. Therefore, it is recommended to use Pearson's correlation and principal component analysis in future investigations of new plant-based proteins.

Gastrophysical and chemical characterization of structural changes in cooked squid mantle.

Squid (Loligo forbesii and Loligo vulgaris) mantles were cooked by sous vide cooking using different temperatures (46°C, 55°C, 77°C) and times (30 s, 2 min, 15 min, 1 h, 5 h, 24 h), including samples of raw tissue. Macroscopic textural properties were characterized by texture analysis (TA) conducted with Meullenet-Owens razor shear blade and compared to analysis results from differential scanning calorimetry. The collagen content of raw tissues of squid was quantified as amount of total hydroxyproline using ultra-high-performance liquid chromatography. Structural changes were monitored by Raman spectroscopy and small-angle X-ray scattering and visualized by second harmonic generation microscopy. Collagen in the squid tissue was found to be highest in arms (4.3% of total protein), then fins (3.0%), and lowest in the mantle (1.5%), the content of the mantle being very low compared to that of other species of squid. Collagen was found to be the major protein responsible for cooking loss, whereas both collagen and actin were found to be key to mechanical textural changes. A significant decreased amount of cooking loss was obtained using a lower cooking temperature of 55°C compared to 77°C, without yielding significant textural changes in most TA parameters, except for TA hardness which was significantly less reduced. An optimized sous vide cooking time and temperature around 55-77°C and 0.5-5 h deserves further investigation, preferably coupled to sensory consumer evaluation. PRACTICAL APPLICATION: The study provides knowledge about structural changes during sous vide cooking of squid mantle. The results may be translated into gastronomic use, promoting the use of an underutilized resource of delicious and nutritious protein (Loligo vulgaris and Loligo forbesii).

Umami potential of fermented beverages: Sake, wine, champagne, and beer.

The free amino acid (FAA) contents of a special selection of fermented beverages have been measured by ultra-high performance liquid chromatography (UHPLC). The selection, which includes 8 sakes, 9 white, rosé, and sparkling wines, 9 genuine champagnes, as well as 5 types of beer, was made to uncover the umami potential of different types of fermented beverages, in particular whether long yeast contact and ageing may influence the contents of free glutamate that is known to elicit umami sensation. The data show that in particular sakes as well as some beers, wines and champagnes with long yeast contact contain appreciable amounts of free glutamate. The results are discussed in the context of food pairing where umami synergy can be achieved by combining fermented beverages with long yeast contact with food rich in free nucleotides.

Prediction of survival in amyotrophic lateral sclerosis: a nationwide, Danish cohort study.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease with great heterogeneity. Biological prognostic markers are needed for the patients to plan future supportive treatment, palliative treatment, and end-of-life decisions. In addition, prognostic markers are greatly needed for the randomization in clinical trials. OBJECTIVE: This study aimed to test the ALS Functional Rating Scale-Revised (ALSFRS-R) progression rate (ΔFS) as a prognostic marker of survival in a Danish ALS cohort. METHODS: The ALSFRS-R score at test date in association with duration of symptoms, from the onset of symptoms until test date, (defined as ΔFS') was calculated for 90 Danish patients diagnosed with either probable or definite sporadic ALS. Median survival time was then estimated from the onset of symptoms until primary endpoint (either death or tracheostomy). ΔFS' was subjected to survival analysis using Cox proportional hazards modelling, log-rank test, and Kaplan-Meier survival analysis. RESULTS AND CONCLUSIONS: Both ΔFS' and age was found to be strong predictors of survival of the Danish ALS cohort. Both variables are easily obtained at the time of diagnosis and could be used by clinicians and ALS patients to plan future supportive and palliative treatment. Furthermore, ΔFS', is a simple, prognostic marker that predicts survival in the early phase of disease as well as at later stages of the disease.

Complement Profiles in Patients with Amyotrophic Lateral Sclerosis: A Prospective Observational Cohort Study.

BACKGROUND: The complement system has been suggested to be involved in the pathophysiology of amyotrophic lateral sclerosis (ALS), a progressive motor neuron disease. In the present study, we compared levels of selected complement markers to clinical outcome in ALS patients. METHODS: This observational, explorative cohort study included 92 ALS patients, 61 neurological controls (NCs) admitted for suspected aneurysmal subarachnoid haemorrhage, and 96 neurologically healthy controls (NHCs). Peripheral blood and cerebrospinal fluid (CSF) were obtained for the measurement of ficolin-1, -2, and -3; collectin-11, MBL, MASP-3, MAP-1, C4, C3, PTX-3, and complement activation products C4c, C3bc, and sC5b-9. We recorded clinical outcomes of ALS patients for 24 to 48 months after inclusion in order to analyse the effects of the complement markers on survival time. RESULTS: Compared with both control groups, ALS patients exhibited increased collectin-11, C4 and sC5b-9 in plasma, as well as increased ficolin-3 in CSF. Ficolin-2 was significantly decreased in plasma of the ALS patients compared with NHCs, but not with NCs. The concentration of collectin-11, C3 and C3bc correlated negatively with the revised ALS functional rating scale (ALSFRS-R). No association was found between levels of complement markers and survival as estimated by hazard ratios. CONCLUSION: ALS patients exhibit aberrant expression of selected mediators of the lectin complement pathway as well as increased activation of the terminal complement pathway, corroborating the notion that the complement system might be involved in the pathophysiology of ALS.

Umami synergy as the scientific principle behind taste-pairing champagne and oysters.

Food and flavour pairing are commonly used as an empirically based phenomenology by chefs and food innovators for creating delicious dishes. However, there is little if any science behind the pairing systems used, and it appears that pairing is determined by food culture and tradition rather than by chemical food composition. In contrast, the pairing implied by the synergy in the umami taste, elicited by free glutamate and free nucleotides, is scientifically founded on an allosteric action at the umami receptor, rendering eggs-bacon and cheese-ham delicious companions. Based on measurement of umami compounds in champagnes and oysters we suggest that a reason why champagne and oysters are considered good companions may be the presence of free glutamate in champagne, and free glutamate and 5'-nucleotides in oysters. By calculations of the effective umami potential we reveal which combinations of oysters and champagnes lead to the strongest umami taste. We also show that glutamate levels and total amount of free amino acids are higher in aged champagnes with long yeast contact, and that the European oyster (Ostrea edulis) has higher free glutamate and nucleotide content than the Pacific oyster (Crassostrea gigas) and is thus a better candidate to elicit synergistic umami taste.

Neuroplasticity induced by general anaesthesia: study protocol for a randomised cross-over clinical trial exploring the effects of sevoflurane and propofol on the brain - A 3-T magnetic resonance imaging study of healthy volunteers.

BACKGROUND: Although used extensively worldwide, the effects of general anaesthesia on the human brain remain largely elusive. Moreover, general anaesthesia may contribute to serious conditions or adverse events such as postoperative cognitive dysfunction and delirium. To understand the basic mechanisms of general anaesthesia, this project aims to study and compare possible de novo neuroplastic changes induced by two commonly used types of general anaesthesia, i.e. inhalation anaesthesia by sevoflurane and intravenously administered anaesthesia by propofol. In addition, we wish to to explore possible associations between neuroplastic changes, neuropsychological adverse effects and subjective changes in fatigue and well-being. METHODS: This is a randomised, participant- and assessor-blinded, cross-over clinical trial. Thirty healthy volunteers (male:female ratio 1:1) will be randomised to general anaesthesia by either sevoflurane or propofol. Multimodal magnetic resonance imaging (MRI) of the brain will be performed before and after general anaesthesia and repeated after 1 and 8 days. Each magnetic resonance imaging session will be accompanied by cognitive testing and questionnaires on fatigue and well-being. After a wash-out period of 4 weeks, the volunteers will receive the other type of anaesthetic (sevoflurane or propofol), followed by the same series of tests. Primary outcomes: changes in T1-weighted 3D anatomy and diffusion tensor imaging. SECONDARY OUTCOMES: changes in resting-state functional magnetic resonance imaging, fatigue, well-being, cognitive function, correlations between magnetic resonance imaging findings and the clinical outcomes (questionnaires and cognitive function). Exploratory outcomes: changes in cerebral perfusion and oxygen metabolism, lactate, and response to visual stimuli. DISCUSSION: To the best of our knowledge, this is the most extensive and advanced series of studies with head-to-head comparison of two widely used methods for general anaesthesia. Recruitment was initiated in September 2019. TRIAL REGISTRATION: Approved by the Research Ethics Committee in the Capital Region of Denmark, ref. H-18028925 (6 September 2018). EudraCT and Danish Medicines Agency: 2018-001252-35 (23 March 2018). www.clinicaltrials.gov , ID: NCT04125121 . Retrospectively registered on 10 October 2019.

Amyotrophic lateral sclerosis and the innate immune system: protocol for establishing a biobank and statistical analysis plan.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a devastating, progressive disease that causes degeneration of the motor neurons leading to paresis of the bulbar and the skeletal musculature. The pathogenesis of ALS remains unknown. We will test the hypothesis that the complement system is involved in the pathophysiology of ALS. This protocol article describes our efforts to establish a national Danish ALS biobank. The primary aim is to obtain biological material from patients with ALS for the current study as well as for future studies. METHODS AND ANALYSIS: We intend to establish an observational ALS biobank; some of the material from this biobank will be used for a prospective, observational case-control study. The participants are patients with ALS, neurologically healthy controls and non-ALS neurological controls. Each participant consents to be interviewed and to donate blood and cerebrospinal fluid to the biobank. Analysis of the complement system will be carried out on the three groups of patients and compared. ETHICS AND DISSEMINATION: The project has been approved by the Committees on Health Research Ethics in the Capital Region of Denmark (Approval number H-16017145) and the Danish Data Protection Agency (file number 2012-58-0004). All results will be published in peer-reviewed, medical journals and presented at scientific conferences. TRIAL REGISTRATION NUMBER: NCT02869048.

Limitation of Maillard Reactions in Lactose-Reduced UHT Milk via Enzymatic Conversion of Lactose into Galactooligosaccharides during Production.

Lactose-hydrolyzed (LH) ultrahigh temperature (UHT) processed milk is more prone to Maillard reactions and formation of advanced glycation end products (AGEs) during processing and storage than conventional (CON) UHT milk because of the presence of free galactose and glucose. Commercially available ß-d-galactosidases with transgalactosylating activity can incorporate galactose into galactooligosaccharides (GOSs) and potentially limit Maillard reactions in this lactose-reduced GOS-containing milk. The aim of this study was to examine the extent of Maillard reactions in a lactose-reduced GOS milk compared to LH and CON milk after UHT processing. The GOS milk had significant lower levels of lysine- and arginine-derived AGEs compared to LH milk, while their concentrations were similar to those found in CON milk. The total concentration of measured Arg-derived AGEs was similar to the total concentration of Lys-derived AGEs in the three types of milk, indicating that Arg is an important source of AGEs in milks. Interestingly, the GOS milk generated threefold higher concentrations (up to 330 ± 6 µM) of 3-deoxyglucosone (3-DG, a C6 α-dicarbonyl). These results demonstrate that GOS milk could be a potential alternative for LH milk for lactose-intolerant individuals, although further studies are needed to understand the increased formation of 3-DG in GOS-containing milk.

Continuous EEG Monitoring in a Consecutive Patient Cohort with Sepsis and Delirium.

BACKGROUND: Delirium is common during sepsis, although under-recognized. We aimed to assess the value of continuous electroencephalography (cEEG) to aid in the diagnosis of delirium in septic patients. METHODS: We prospectively evaluated 102 consecutive patients in a medical intensive care unit (ICU), who had sepsis or septic shock, without evidence of acute primary central nervous system disease. We initiated cEEG recording immediately after identification. The median cEEG time per patient was 44 h (interquartile range 21-99 h). A total of 6723 h of cEEG recordings were examined. The Confusion Assessment Method for the ICU (CAM-ICU) was administered six times daily to identify delirium. We analyzed the correlation between cEEG and delirium using 1252 two-minute EEG sequences recorded simultaneously with the CAM-ICU scorings. RESULTS: Of the 102 included patients, 66 (65%) had at least one delirium episode during their ICU stay, 30 (29%) remained delirium-free, and 6 (6%) were not assessable due to deep sedation or coma. The absence of delirium was independently associated with preserved high-frequency beta activity (> 13 Hz) (P < 10-7) and cEEG reactivity (P < 0.001). Delirium was associated with preponderance of low-frequency cEEG activity and absence of high-frequency cEEG activity. Sporadic periodic cEEG discharges occurred in 15 patients, 13 of whom were delirious. No patient showed clinical or electrographic evidence of non-convulsive status epilepticus. CONCLUSIONS: Our findings indicate that cEEG can help distinguish septic patients with delirium from non-delirious patients.

Liquid chromatography quadrupole-Orbitrap mass spectrometry for the simultaneous analysis of advanced glycation end products and protein-derived cross-links in food and biological matrices.

Advanced glycation end products (AGEs) and protein cross-links have been extensively investigated in both food and biomedical fields over the past years. Although there are a few chromatographic and immunological methods for the analysis of selected AGEs, there is no method available for comprehensive simultaneous analysis of major AGEs found in processed foods and biological samples. In the present study, we have reported a validated UHPLC-MS/MS method for simultaneous identification and quantification of 15 different AGEs, furosine (an indicator of Amadori products), 2 protein-derived cross-links (lanthionine and lysinoalanine) and 2 amino acids (Lys and Arg). The analytes were separated on a reversed phase C-18 column and quantified accurately based on the isotope dilution method, where 9 stable isotope-labelled internal standards were used to quantify 20 different analytes using an Orbitrap mass analyzer. The method showed acceptable linearity, accuracy and precision. The LOD and LOQ values in plasma were in the range of 0.30-19.02 and 0.87-57.06 ng/mL, respectively. The recovery values at the three spiked levels were in the range of 71-110%, with some exceptions. The intraday and interday precision were in the range of 1.5-13.2%, however, quantification of N-ɛ-(carboxymethyl)lysine accompanied slightly higher interday precision (30.7%). The applicability of the method was successfully assessed by analyzing AGEs and protein cross-links in six different complex matrices including Ultra-High Temperature (UHT) processed milk, roasted chicken breast meat, roasted chicken skin, roasted pork liver, bovine plasma and perfusion liquid.

Multiresponse Kinetic Modeling of Heat-Induced Equilibrium of ß-Carotene cis-trans Isomerization in Medium-Chain Triglyceride Oil.

The kinetics and mechanism of the stepwise cis-trans isomerization reactions of all-trans-ß-carotene dissolved in MCT (medium-chain triglyceride) oil at temperatures in the range of 80-160 °C have been analyzed using multiresponse modeling. Quantitation of the cis-isomers was performed using HPLC-DAD and quantitation at the reaction isosbestic point at 421 nm. Multiresponse kinetic modeling using the Bayesian criterion was initially performed at 120 °C to determine the best model. Subsequently, the reparametrized Arrhenius equation was used to calculate the activation energies of all reactions. The equilibrium constants for the individual isomerization reactions were determined from the rate constants and the final product distributions. The enthalpies and entropies of the isomerization reactions were determined from the temperature dependence of the equilibrium constants. The 13-cis and 13,13'-di-cis isomers were found to be the fastest formed isomers followed by the 9-cis, 9,13-di-cis, and 13,15-di-cis isomers, where the latter was found to be formed from 13-cis and not the 15-cis isomer. The relative free energies of the ß-carotene isomers were determined as all-trans < 13-cis < 9-cis < 13,13'-di-cis < 9,13-di-cis ≈ 15-cis < 13,15-di-cis. The entropic contribution of each reaction was found to play an important role in the ordering. It is concluded that the ß-carotene system is quite labile at temperatures ranging from 80 to 160 °C and resulting in equilibrium distributions of the cis-trans isomers.

Quantitation of α-Dicarbonyls and Advanced Glycation Endproducts in Conventional and Lactose-Hydrolyzed Ultrahigh Temperature Milk during 1 Year of Storage.

A comprehensive quantitative characterization of Maillard reaction products was carried out for conventional (CON) and lactose-hydrolyzed (LH) ultrahigh temperature (UHT) milk during storage at 20, 30, and 40 °C for 1 year. The accumulation of 3-deoxyglucosone (3-DG) and 3-deoxygalactosone (3-DGal) in LH-UHT milk ranged from 20-fold (at 20 °C) to 44-fold (at 40 °C) higher than that in CON-UHT milk. High temperature storage (40 °C) significantly accelerated the accumulation of 3-DG, 3-DGal, and 5-hydroxymethyl furfural but not the majority of the analyzed advanced glycation endproducts (AGEs). The concentrations of major AGEs including N-ε-carboxymethyllysine (CML), N-ε-carboxyethyllysine (CEL), methylglyoxal-hydroimidazolone isomers (MG-H1/H3), glyoxal-hydroimidazolone isomers (G-H1/H3), and G-H2 detected in CON milk during storage were in the range 12-700, 1-14, 8-45, 4-13, and 1-30 µM, respectively, while they were 30-570, 2-88, 17-150, 9-20, and 5-34 µM, respectively, in LH milk. Pyrraline, S-(carboxymethyl)cysteine (CMC), and glyoxal-lysine dimer were detected in lower levels, while MG-H2, methylglyoxal-lysine dimer, argpyrimidine, glyoxal-lysine-amide, glycolic acid-lysine-amide, and pentosidine were not detected in any of the milk samples. This work demonstrates for the first time that five of the analyzed AGEs (CML, CEL, MG-H1/H3, G-H1/H3, and G-H2) could be selected as markers for evaluation of the extent of the Maillard reaction in UHT milk. These results contribute to a better understanding of how Maillard reactions progress during storage of UHT milk and can be used to develop strategies to inhibit Maillard reactions in LH milk.

Morphology and Structure of Solid Lipid Nanoparticles Loaded with High Concentrations of ß-Carotene.

Solid lipid nanoparticles (SLNs) containing up to 37.5 wt % all-trans ß-carotene in the lipid phase are potential water-dispersible food colorants. SLNs have been made by hot-melt high-pressure homogenization with fully hydrogenated sunflower oil and with polysorbate 80 and sunflower lecithin as stabilizers. Atomic force microscopy revealed the SLNs had thin platelet structures most likely derived from the triglyceride crystal ß-form, as detected by X-ray diffraction. No indications of crystalline ß-carotene were detected. High-performance liquid chromatography analysis showed the extensive isomerization of ß-carotene into more than 10 cis isomers, suggesting that it is present as an amorphous mixture. The high ß-carotene loadings did not affect the triglyceride crystal structure and the morphology of the SLNs. It is suggested the SLNs consist of a platelet core of crystalline triglyceride surrounded by an amorphous ß-carotene-containing layer. The layered structure is suggested to affect the coloring power of the SLNs at ß-carotene loadings above 15 wt % of the lipid phase.

Stabilization of Black Rice (Oryza Sativa, L. Indica) Anthocyanins Using Plant Extracts for Copigmentation and Maltodextrin for Encapsulation.

Black rice (Oryza sativa L. indica) is one of the cereal commodities considered to be a source of anthocyanin. One of the obstacles of using anthocyanins as natural food colorants is their low stability. The objective of this study was to determine the effect of natural plants extracts on anthocyanin copigmentation and to study the stability of the encapsulated copigmented anthocyanin during storage under different temperatures and light exposure. Dried bilimbi leaves (BL) and sow thistle leaves (STL) were extracted using ethanol to obtain the crude flavonoid extract that was subsequently purified using solid phase extraction. Both crude (CBL, CSTL) and purified (PBL, PSTL) extract were used as copigment agents with the molar ratio of 1:0.1 to 1:10 at pH 1 and pH 3. The copigmentation effect was evaluated by measuring the wavelength and absorbance shifts at wavelengths of 500 to 600 nm. The stability of the dried anthocyanin powder was evaluated under different temperatures and light exposure for up to 4 weeks. Anthocyanin was successfully copigmented with BL and STL extracts showing a wavelength shift and absorbance increase at pH 1 and pH 3. Purification of BL enhanced the hyperchromic effect more than that of the crude form, in contrast to the STL. Meanwhile, the retention of absorbance (%) for encapsulated copigmented anthocyanin samples was within 74% to 83% at the end of the storage period. PRACTICAL APPLICATION: Natural food pigment such as anthocyanin obtained from plant extract usually shows very limited stability under various processing conditions. This study shows that color stability of anthocyanin extracted from black rice can be improved by copigmentation with flavonoids extracted from particular plants. Encapsulation of the copigmented anthocyanin could further enhance its color stability. The availability of encapsulated and copigmented anthocyanins with improved color stability is expected to provide more alternatives for especially the beverage industry to choose suitable natural colorant for their products.

Formation of α-Dicarbonyls from Dairy Related Carbohydrates with and without Nα-Acetyl-l-Lysine during Incubation at 40 and 50 °C.

α-Dicarbonyls are reactive intermediates formed during Maillard reactions and carbohydrate degradation. The formation of seven α-dicarbonyls was characterized in solutions containing dairy related carbohydrates (galactose, glucose, lactose, and galacto-oligosaccharides (GOS)) during incubations at 40 and 50 °C with and without Nα-acetyl-l-lysine at pH 6.8 for up to 2 months. The concentrations of α-dicarbonyls in samples of monosaccharides with Nα-acetyl-l-lysine were found to be 3-deoxyglucosone (3-DG) > 3-deoxygalactosone (3-DGal) > glyoxal > glucosone, galactosone > methylglyoxal > diacetyl. The presence of Nα-acetyl-l-lysine resulted in up to 100-fold higher concentrations of C6 α-dicarbonyls but lesser formation of glyoxal in the monosaccharide-containing models compared to what was observed in the absence of Nα-acetyl-l-lysine. Galactose incubated with Nα-acetyl-l-lysine generated the highest concentrations of 3-DGal (up to 130 µM), glyoxal (up to 100 µM), and methylglyoxal (up to 9 µM) compared to the other carbohydrates during incubation. Surprisingly, 3-DG (1500 µM) and 3-DGal (80 µM) were formed at levels of 2 orders of magnitude higher in solutions of GOS in the absence of Nα-acetyl-l-lysine as compared to the other carbohydrates at 40 °C, while GOS generated the lowest levels of glyoxal. GOS are widely used as an ingredient in various types of foods products, and it is therefore of importance to consider the risk of generating high levels of the reactive C6 α-dicarbonyl, 3-DG, in these types of products. This study contributes to the understanding of major α-dicarbonyl formation as affected by the presence of primary amines in GOS-, lactose-, and galactose-containing solutions under moderate heating in liquid foods.