On the manipulation, and meaning(s), of color in food: A historical perspective

Digital image-based chemometrics for food analysis: a practical tutorial and roadmap

Digital images have become a powerful tool for developing analytical methods in food quality control. Unlike conventional analytical signals, images can be processed to extract relevant chemical information, with chemometric techniques enhancing their utility. This review synthesizes applications of digital imaging in food analysis, providing a roadmap from univariate methods to multivariate classification/calibration approaches, illustrated through three case studies demonstrating their potential for food safety and quality. However, the field faces critical challenges, particularly the lack of methodological standardization, as evidenced by diverse applications in literature. Addressing this gap is essential to ensure reliability and reproducibility. Furthermore, the review highlights recent advances, such as hybrid color descriptors, chromaticity maps, deep learning architectures, and time-resolved RGB imaging, that improve the robustness and applicability of these techniques in food science.

Uncovering the light absorption mechanism of the blue natural colorant allophycocyanin from Arthrospira platensis using molecular dynamics

Phycobiliproteins of the cyanobacterium Arthrospira platensis, known as Spirulina, are protein-chromophore complexes which are used by the organism to capture light energy. Allophycocyanin and C-phycocyanin are prominent in providing a natural source of blue food coloring. An unresolved issue remains the rapid loss of the native conformation of the pigment, leading to altered color with changing pH. This study investigates color changes on a quantum mechanics scale. A model was established to predict color shifts upon environmental changes, while proposing a mechanism to elucidate pH-dependent chromophore dynamics. On average, the model predicts a hypsochromic shift of 34 nm, in close alignment with the experimentally determined 36 nm. Results show several key non-covalent interactions governing the dynamics of the pyrrole rings of allophycocyanin, particularly influenced by solvents and pH. Particularly noteworthy are the hydrogen bonds with arginine (R 86) and aspartic acid (D 87), contributing to the distinctive optical absorption properties. These findings aid in pigment selection and the targeting of specific phycocyanin regions for stabilization, reducing the dependence on artificial food colors.

Wild Myrtus communis L. Fruit By-Product as a Promising Source of a New Natural Food Colourant: Optimization of the Extraction Process and Chemical Characterization

Myrtus communis L., as a wild underutilized fruit, was analyzed for its physicochemical properties and bioactive composition, revealing a high anthocyanin content principally concentrated in the peel. Therefore, the anthocyanin extraction conditions through ultrasound-assisted extraction from Myrtus communis L. fruit peels (MCP), considered a by-product, were optimized using response surface methodology (RSM), evaluating four independent extraction variables with total anthocyanin content as the response criterion. As a result, optimal extraction conditions were determined to be 20 min, pH 6, 500 W, and 19.68 g/L, yielding a total anthocyanin content of 47.51 mg cya-3-glu/g. In addition, the optimized colourant extract presented a higher content of bioactive compounds compared to the fruit itself, with 1.4 times higher polyphenols and 1.8 times higher total anthocyanin content, with malvidin-3-O-glucoside as the predominant anthocyanin, evidencing the effectiveness of the proposed extraction process. In conclusion, applying the optimal extraction conditions for MPC enables the production of an extract with remarkable anthocyanin content and other phenolic compounds, making it an excellent candidate as a natural food colourant.

The Role of Fruit Surface Bloom in Consumer Preference for Blueberries: Sensory Evaluation and Multisensory Interactions

Three blueberry cultivars ('San Joaquin', 'Jewel', and 'Snowchaser') were harvested at commercial maturity and subjected to different degrees of fruit surface bloom removal (full natural bloom (FB), partial bloom (PB), and removed bloom (RB)) to assess the importance of the bloom to consumer preference. Sensory evaluation assessed flavor, appearance, and overall acceptance under different conditions (darkness and light). Panelists preferred berries with at least some degree of bloom, as influenced by appearance for all varieties, and in 'Snowchaser' and 'Jewel', flavor acceptance declined when the evaluation allowed the fruit to be visualized. Panelists were prompted to select the attribute most influencing their affective evaluations to better understand the basis for the differences due to the presence of bloom. FB and PB were rated as more appealing, except for 'Jewel', where PB was deemed unattractive. At the same time, bloom presence influenced firmness choices, and sweetness and tartness preferences were affected by both variety and evaluation conditions, suggesting complex interactions in multisensory perception. Principal component analysis reinforced the idea that treatments with bloom removal were less accepted overall, while 'Snowchaser' samples were consistently well-liked relative to the other two varieties. These findings highlight the importance of bloom presence in blueberry quality perception and consumer behavior.

Impact of Button Mushroom Stem Residue as a Functional Ingredient for Improving Nutritional Characteristics of Pizza Dough

In this study, the formulation of doughs was investigated using varying percentages of Agaricus bisporus flour, with the aim of utilizing mushroom stem fragments, typically considered production waste. The stem residues were collected from a mushroom cultivation facility, cleaned, and washed to remove impurities. The material was then subjected to two different drying methods: conventional dehydration and freeze-drying. After drying, the material was ground to produce mushroom flour. Doughs were formulated with different proportions of this flour and analyzed for texture profile, color, nutritional value, phenolic content, antioxidant activity, and sensory characteristics. The inclusion of mushroom flour resulted in darker doughs, particularly when the flour was obtained through conventional dehydration due to oxidation processes. This substitution also affected texture parameters, leading to increased hardness and reduced elasticity in most treatments compared to the control sample. In addition, cohesiveness progressively decreased from 0.35 in the control to 0.14 in the sample made with 100% dehydrated flour and 0.20 in the sample made with 100% freeze-dried flour, resulting in brittle doughs. The most significant impact on nutritional value was an increase in protein, fat, and dietary fiber levels, reaching values over 5% of crude fiber in the sample to which 50% of dehydrated mushroom flour was added. Additionally, mushroom flours exhibited a high proportion of phenolic compounds, reaching values near 700 mg gallic acid/100 g in the flour from freeze-dried samples and 320 mg gallic acid/100 g in the flour from dehydrated samples. These values reflect a higher content of phenolic compounds in products made with mushroom flours and an increased antioxidant capacity compared to the control sample. Sensory evaluation showed that the texture remained unaffected; however, flavor perception was altered at a 50% mushroom flour substitution. In terms of external appearance, only the 25% freeze-dried mushroom flour formulation was statistically similar to the control, while all other treatments were rated lower.

Color Matters: A Study Exploring the Influence of Packaging Colors on University Students' Perceptions and Willingness to Pay for Organic Pasta

The organic food market's rapid expansion necessitates an understanding of factors influencing consumer behavior. This paper investigates the impact of packaging colors on perceptions and willingness to pay (WTP) for organic foods, utilizing an experimental auction among university students. Drawing on previous research, we explore how colors influence perceived healthiness, premiumness, trust, and sustainability. The results indicate nuanced responses to different colors, emphasizing the need for businesses to adopt tailored packaging strategies. White and green dominate organic food packaging, aligning with associations of freshness and health. However, the study uncovers varied consumer responses, suggesting a more intricate relationship between color, trust, premiumness, and healthiness perceptions. Demographic factors such as age, gender, income, and residence areas influence WTP for organic foods with different colors, emphasizing the importance of diverse consumer segments in marketing strategies. Trust and perceived premiumness significantly influence WTP, highlighting their pivotal role in consumer valuation. The results highlight that green packaging builds trust among non-organic buyers, while organic buyers are influenced by a broader range of colors that emphasize premiumness and healthiness. The study concludes that businesses in the organic food market should carefully consider color choices in branding and packaging to effectively communicate product qualities and align with consumer values.

Use of Different O/W or W/O Emulsions as Functional Ingredients to Reduce Fat Content and Improve Lipid Profile in Spanish Cured Processed Meat Product ('Chorizo')

In this work, three out of five types of oil-in-water and water-in-oil emulsions were selected to replace pork backfat to reduce the fat content and the improve monounsaturated and polyunsaturated fatty acid content in dry cured sausage ('chorizo'). Different characteristics of the new product were studied: the texture profile, color, nutritional value, lipid profile, vitamin E and thiobarbituric acid (TBA) and sensory qualities. The use of emulsions to replace the animal fat affected all color parameters, obtaining darker, less red and yellow products, which could impact the consumer's purchase intention. This replacement also altered the texture parameters, increasing or decreasing the hardness in comparison with the control sample. The cohesiveness, however, decreased in all cases, which meant that when the samples are cut for consumption, they disintegrated more than the traditional ones. The most relevant aspect for nutritional value is that the use of the new emulsions helped to reduce the total fat and energy value of the reformulated samples. The most significant aspect is that this reformulation helped to reduce the fat content-specifically, saturated fat-while increasing the content of Omega 3/6. The new formulas contained significant quantities of TBA and vitamin E when comparing them with the traditional product.

Influence of time-temperature in the antioxidant activity, anthocyanin and polyphenols profile, and color of Ardisia compressa K. extracts, with the addition of sucrose or citric acid

The objective of this study was to analyze and optimize the influence of heating time and citric acid (CA) or sucrose addition of Ardisia compressa K. extracts on phenolic compounds (TPC), monomeric anthocyanins (MAA), antioxidant activity (TAC), color density (CD), and hue tint (HT), using a full factorial design. Extractions were performed: temperature (25, 50, or 70 °C), time (15, 30, 60, or 90 min), CA (0.0 or 0.02 g), and sucrose (0.0 or 5.0 g). HPLC-DAD-ESI-MS was conducted in extracts without additives and with the addition of CA (0.02 g) or sucrose (5.0 g), at 25, 50, or 70 °C for 15 min. CA-added extracts showed maximum TPC, MAA, TAC (DDPH and ABTS assays), and CD values, with the lowest HT values. Malvidin 3-O-galactoside and myricetin-O-hexoside were the predominant anthocyanin and non-anthocyanin polyphenols. Time, temperature, and solute influenced the optimized extraction of TPC, MAA, anthocyanins, TAC, CD, and HT.