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•S. bacillaris strains showed genomic differences relevant to the green scale colour.•Nucleotide variations in nineteen genes had a significant impact on phenotypes.•The interplay ...between fermentation kinetics and wine colour is strain-dependent.•FRI751 conferred more brilliance to the fermented synthetic must.•Changes in wine colour are correlated with yeast strains.
This study explores the biological mechanisms behind colour changes in white wine fermentation using different strains of Starmerella bacillaris. We combined food engineering, genomics, machine learning, and physicochemical analyses to examine interactions between S. bacillaris and Saccharomyces cerevisiae. Significant differences in total polyphenol content were observed, with S. bacillaris fermentation yielding 6 % higher polyphenol content compared to S. cerevisiae EC1118. Genomic analysis identified 12 genes in S. bacillaris with high variant counts that could impact phenotypic properties related to wine color. Notably, SNP analysis revealed numerous missense and synonymous variants, as well as stop-gained and start-lost variants between PAS13 and FRI751, suggesting changes in metabolic pathways affecting pigment production. Besides that, high upstream gene variants in SSK1 and HIP1R indicated potential regulatory changes influencing gene expression. Fermentation trials revealed FRI751 consistently showed high antioxidant activity and polyphenol content (Total Polyphenol: 299.33 ± 3.51 mg GAE/L, DPPH: 1.09 ± 0.01 mmol TE/L, FRAP: 0.95 ± 0.02 mmol TE/L). PAS13 exhibited a balanced profile, while EC1118 had lower values, indicating moderate antioxidant activity. The Weibull model effectively captured nitrogen consumption dynamics, with EC1118 serving as a reliable benchmark. The scale parameter delta for EC1118 was 23.04 ± 2.63, indicating moderate variability in event times. These findings highlight S. bacillaris as a valuable component in sustainable winemaking, offering an alternative to chemical additives for maintaining wine quality and enhancing colours profiles. This study provides insights into the biotechnological and fermented food systems applications of yeast strains in improving food sustainability and supply chain, opening new avenues in food engineering and microbiology.
The application of dry aging on fish is increasing in restaurants worldwide. This process determines fluid loss, changes in muscle texture, and the development of a more concentrated flavour ...appreciated by consumers. Despite the growing popularity in the foodservice industry, there is a lack of data on potential risks and quality conditions of dry-aged fish. This study was aimed at assessing the safety for consumption of whole rainbow trout subjected to dry aging in a local restaurant (Turin, Italy). Quantitative microbiological analyses and detection of foodborne pathogens were performed on dorsal, ventral muscles, and skin samples at day 0, 3, 6, 10, and 14 of dry aging. Changes in water activity (aw), pH, colour, and biogenic amines in muscle were checked at each sampling point. Almost all the microbiological indicators were below the quantification limits in muscle until day 6 of dry aging, while higher but still acceptable loads were observed at day 10. At day 14, yeasts and moulds exceeded the acceptable level in one case (3.3 ± 0.4 log10 CFU/g) in ventral muscle and counts of Pseudomonas spp. (from 6.1 ± 0.8 to 6.4 ± 0.5 log10 CFU/g), total mesophilic (from 4.4 ± 0.3 to 5.3 ± 0.7 log10 CFU/g), and psychrophilic (from 5.4 ± 0.1 to 5.8 ± 0.3 log10 CFU/g) bacteria indicated the approaching of spoilage. Detection of Listeria monocytogenes and Staphylococcus aureus was always negative during the trials. Minimal changes of pH and colour were observed, while aw values followed a decreasing trend during dry aging. Putrescine was the only detectable amine, with a maximum concentration of 2.05 ± 0.02 mg/kg at day 14. In this study, dry-aged rainbow trout was safe for consumption and 10 days was the most appropriate curing time with 3 °C and 78% of relative humidity. Further studies at different environmental conditions and on other fish species are needed for a comprehensive risk assessment of this fast-growing practice in the restaurant sector.
•Microbial loads remain within acceptable levels until day 10 of dry aging.•Listeria monocytogenes and Staphylococcus aureus are never detected during trials.•Putrescine is the only detectable amine, peaking 2.05 ± 0.02 mg/kg at day 14.•A ten-day curing period is the most suitable at 3 °C and 78% of relative humidity.
The colour distinction between male and female, and between young and mature male dragonflies of the genera Crocothemis and Sympetrum arises from simple redox chemistry. This natural phenomenon has ...inspired the development of a class of electrochromic device
Summary
This study investigated the impact of heating temperatures (70 °C to 90 °C for up to 14 h) on lycopene and β‐carotene degradation kinetics in gac aril paste. Carotenoids extracted via ...low‐volume hexane‐assisted ultrasonic extraction revealed a first‐order degradation pattern with high correlation coefficients (0.96–0.97). Lycopene degraded faster at 90 °C (
k
= 12.05 × 10
2
h
−1
) than at 70 °C (5.41 × 10
2
h
−1
), while β‐carotene displayed relatively slower degradation. Corresponding half‐life (
t
1/2
) values for lycopene ranged from 5.75 to 12.81 h, while β‐carotene displayed values of 9.48–20.2 h. β‐carotene showed superior thermal stability compared to lycopene across all temperatures. Additionally, colour changes indicated decreased brightness with increasing temperature. The DPPH radical scavenging activity and FRAP values decreased during gac fruit heating. Overall, this study emphasises temperature‐induced declines in lycopene and β‐carotene levels in gac aril paste and offers insights into their degradation kinetics under thermal processing.
There are several thousand different cultivars of apple trees but only a limited number are cultivated on an industrial scale. Old cultivars can be useful, for example, in the processing industry due ...to their different composition. In many cases, they have higher organic acid content. The content of mineral components, colour, and polyphenols in the fruit of 7 old apple tree cultivars, growing in the Wolinski National Park, was studied. The changes that occurred in the fruit after freeze-drying were also evaluated. The trees from which the fruit was picked for analysis, despite the lack of chemical protection, were fruiting and the apples had only a few symptoms of damage caused by pests or diseases. The fruit was characterised by a high soluble solids content (14.4-16.4%), in which sugars and especially fructose dominated. The number of organic acids varied greatly and ranged from 0.27 (Oberlander Himbeerapfel) g to 1.07 g/100 g (Winter Goldparmane). The content of polyphenols in fresh apples ranged from 186 mg (Horneburger Pfannkuchenapfel) to 354 mg/100 g (Winter Goldparmane) and increased after freeze-drying from 666 mg (Weisser Winterkalvill) to 1486 mg/100 g (Winter Goldparmane). The dominant group of polyphenolic compounds was phenolic acid. The freeze-drying process caused unfavourable changes in the colour of the pulp. The fruits of Oberlander Himbeerapfel cultivar were most susceptible to these changes. However, the least darkened fruit of Horneburger Pfannkuchenapfel.
Excessive heating with hot-air oven dryers produces considerable losses in
the quality of dried tomatoes, particularly in the organoleptic and colour
characteristics. Thus, process parameters need to ...be optimised to minimise
detrimental colour quality changes that might not be easily achieved using
sophisticated colour detection devices. While a sizable number of studies on
the drying of tomatoes, soft-computational modelling and sensitivity
analysis of tomatoes' colour characteristics during convective hot-air
drying using Adaptive Neuro-fuzzy Inference System (ANFIS) and Artificial
Neural Network (ANN) are still unreported. Therefore, this work presents a
soft-computing prediction of tomatoes' colour characteristics during
convective hot-air drying. The tomatoes were pretreated, sliced, and dried
at 40, 50, and 60?C. The colour characteristics (L*, a*, b*, a*/b* change
in colour, browning index, hue, and chroma) before and after were
determined, and the data was used to train ANN and ANFIS models. The model's
predictive performance was determined by calculating the coefficient of
determination (R2), Root Means Squared Error (RMSE), and Mean Absolute Error
(MAE) between predicted and experimental results. The results showed a range
of 26.83 - 43.27, 22.79 - 42.10, 16.99 - 33.72, 1.11 - 1.34, 16.70 - 42.71,
16.94 - 62.37, 28.43 - 53.94, and 0.84 - 0.93, respectively, for the colour
characteristics. The ANFIS model demonstrates a meaningful relationship
between colour changes and drying conditions with a higher R2 (0.9999) and
lower RMSE (0.0452) and MAE (0.0312) than ANN. Thus, the ANFIS model is
reliable for prediction and can be further used for fuzzy-based controller
process design.
•We examine impact of UV radiation on the CO2 laser treated lime wood.•We examine colour and structural changes of lignin and polysaccharides.•The difference of lightness ΔL* after irradiation by the ...xenon tube attained positive values.•The biggest changes caused by UV radiation were found on the surface of untreated lime wood.•After exposure to UV radiation, photodegradation changes in lignin (non-conjugated CO bonds) and in cellulose (asymmetric COC vibrations) were observed.
The paper deals with the study of colour and chemical changes in lime wood treated with CO2 laser and subsequently subjected to the impact of xenon lamp radiation with the aim to simulate the ageing of wood due to the UV component of solar radiation. The separated areas were created on the surface of lime tree (Tilia vulgaris, L.) using CO2 laser (wavelength of 10.6μm), each of them using at different exposures (expressed as the irradiation dose within a range of 8–29 J·cm−2). Such treated samples were subsequently irradiated using xenon lamp (wavelength of 340nm, power of 1800W) for 100h. The colour changes were monitored using spectrophotometer and were quantified by means of colour differentiations in colorimetric space of CIELab. The chemical changes in the main wood components were determined by ATR-FTIR spectrometry. The difference of lightness ΔL* after irradiation by the xenon lamp attained positive values, which means the lightening of the surface (with the exception of laser-untreated wood, where darkening was observed). After exposure to UV radiation, photodegradation changes in lignin (non-conjugated CO bonds) and in cellulose (asymmetric COC vibrations) were observed. The biggest changes caused by UV radiation were found on the surface of untreated lime wood.
A prototype far-infrared (FIR) dryer was developed to study the effects of far-infrared radiation on physicochemical properties changes of rice flour and energy consumption for gelatinization. A thin ...layer of rice flour was exposed to different FIR intensities (11.2, 8.5, and 7.8 kW m
−2
) and different time intervals (2-16 s). The degree of gelatinization, viscosity changes, color changes, acidity changes during storage, and energy consumption for gelatinization were measured. The degree of gelatinization, color changes, and viscosity increased with FIR intensity and exposure time. Gelatinized rice flour showed significantly (p < 0.05) lower acidity development compared to non-gelatinized flour during storage. The drying rate increased, and specific energy consumption decreased with increasing FIR intensity. It was found that optimum gelatinization can be achieved at 11.2 kW m
−2
FIR intensity for 16 s. All these results confirm that FIR is an effective source of rice flour roasting.
As a result of contemporary ecological and sustainable movements, a number of constructions from wood, as the only renewable building material, is still increasing. In accordance with these trends, ...wood elements are often left untreated. The presented study is aimed to characterize and compare a surface degradation of untreated wood caused by weathering. Weathering characteristics of softwoods and hardwoods (spruce, pine, Douglas fir, larch, oak, black locust, maple, poplar and alder) during twelve months of exposure in the climatic conditions of Central Europe were determined. All the wood species were characterized by colour and gloss changes and increasing roughness. The lowest discoloration was observed for oak and the highest one for spruce wood, respectively. The lowest changes of roughness were observed for alder, the highest for spruce wood. The depth of colour changes was relatively similar among the softwoods. Regarding hardwoods, it varied more. The values of total colour changes had a significant correlation with the depth values of these colour changes. Maple, alder and poplar samples were characterized by the presence of mould and blue-stain fungi. Douglas fir wood was found to be the most liable for the formation of cracks.
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