Color Compounds Research Articles

Use of Olive and Sunflower Oil Hydrogel Emulsions as Pork Fat Replacers in Goat Meat Burgers: Fat Reduction and Effects in Lipidic Quality.

Diversified strategies to incorporate healthier lipids in processed meat products are being developed. Alternative fat sources to replace animal fat associated with the reduction of fat content are some of the methods used to obtain healthier meat products well recognized by consumers. In order to create a healthier product that can also be consumed in the Halal and Kosher consumer markets, an experimental study was developed to assess the effects of replacing the pork fat (4%) with the same amount of hydrogel emulsion incorporating olive oil or sunflower oil. Three burgers were randomly selected from each lot manufactured and analyzed in triplicate. Burgers were physicochemical analyzed for pH, water activity, composition, fatty acid profile, color, yield, texture, oxidative stability, and volatile compounds and compared according to the fat source. Burgers with hydrogel emulsions can be considered reduced-fat meat products with a healthier fatty acid profile than pork fat burgers. The use of hydrogel emulsions did not negatively affect the quality characteristics assessed in the product and improved the oxidative stability during the storage of cooked burgers. By the characteristics and formulations evaluated, the replacement of pork fat with olive oil hydrogel emulsion proved to be the most effective strategy for obtaining a healthier goat meat product.

Effects of different processing methods on the biochemical composition, color and non-volatile taste active compounds of whiteleg shrimp (Litopenaeus vannamei)

This study determined the biochemical composition, color change, and non-volatile taste-active composition in raw (FSM), boiled (BSM), hot air-dried (HSM), microwave-dried (MSM), and roasted (RSM) whiteleg shrimp meat. All the treatments significantly influenced the biochemical and taste profile of whiteleg shrimp. Processing primarily affected the color and was measured in terms of total color difference (ΔE) and hue angle (H°) values. The fatty acid profiles of FSM and BSM were similar and different from the remaining groups. Moreover, boiling has reduced the content of taste compounds except glucose significantly (P < 0.05) compared to other groups. For the taste evaluation, equivalent umami concentration (EUC) was determined for all the groups and is significantly different (P < 0.05) in the order of MSM>RSM>HSM>FSM>BSM. This study demonstrated that microwave drying showed a significant increase in the content of taste components and the umami flavor of whiteleg shrimp compared to other processing methods.

Low-Cost Nonreversible Electronic-Free Wireless pH Sensor for Spoilage Detection in Packaged Meat Products.

Contamination of meat with pathogenic microorganisms can cause severe illnesses and food waste, which has significant negative impacts on both general health and the economy. In many cases, the expiration date is not a good indicator of meat freshness as there is a high risk of contamination during handling throughout the supply chain. Many biomarkers, including color, odor, pH, temperature, and volatile compounds, are used to determine spoilage. Among these, pH presents a simple and effective biomarker directly linked to the overgrowth of bacteria and degradation of the meat tissue. Low-cost methods for wireless pH monitoring are crucial in detecting spoilage on a large commercial scale. Existing technologies are often limited to short-range detection, with the use of batteries and different electronic components that increases both the manufacturing complexity and cost of the final device. To address these shortcomings, we have developed a cost-effective wireless pH sensor, which uses passive resonant frequency (RF) sensing, combined with a pH-responsive polymer that can be placed within packaged meat products and provide a remote assessment of the risk of microbial spoilage throughout the supply chain. The sensor tag consists of a sensing resonator coated with a pH-sensitive material and a passivated reference resonator operating in a differential frequency configuration. Upon exposure to elevated pH levels >6.8, the coating on the sensing resonator dissolves, which in turn results in a distinct change in the resonant frequency with respect to the reference resonator. Systematic theoretical and experimental results at different pH levels demonstrated that a 20% shift in resonant frequency demarcates the point for spoilage detection. As a proof of concept, the performance of the sensor in remotely detecting the risk of food spoilage was validated in packaged poultry over 10 days. The sensor fabrication process takes advantage of recent developments in the scalable manufacturing of flexible, low-cost devices, including selective laser etching of metalized plastic films and doctor-blade coating of stimuli-responsive polymer films. Furthermore, the biocompatibility of all the materials used in the sensor was confirmed with human intestinal cells (HCT-8 cells).

Treatment of kraft black liquor using basidiomycete and ascomycete fungi

The Kraft Black Liquor effluent generated by the pulp and paper industry is a highly alkaline solution with high chemical oxygen demand (COD), phenolic content, toxicity, and low biodegradability. Currently, it is usually concentrated and used as combustible in cogeneration systems. However, the profitability of this management depends on the unstable energy prices. As a possible alternative, in this work, different fungi have been used to treat this polluting wastewater. Tests were carried out at 25 ºC and 150 rpm for 10 days in a batch reactor. Two fungi capable of releasing suitable enzymes have been tested, i.e., Aspergillus uvarum and Phanerochaete chrysosporium. The effluent was treated with and without solids and with and without pH control. In all cases, the evolution of COD, biological oxygen demand (BOD5), colour index, and the concentration of reducing sugars and phenolic compounds were analysed. Besides, the enzymatic activities manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase (Lac) were measured. Results showed that the presence or absence of solid did not affect the biodegradation process, achieving similar efficiencies. Bioremediation with P. chrysosporium allowed to obtain removals of COD, colour and phenolic compounds of 65 %, 37 % and 56 %, respectively, while A. uvarum achieved 61 %, 81 % and 67 %, for the best conditions tested. These results give good perspectives for application of both fungi for problematic industrial wastewaters, such as black liquor. It is especially interesting the good results obtained with A. uvarum, which has not been previously tested for the treatment of effluents from the paper industry.

The Effectiveness of Moringa Oleifera in Purifying Pegasius SP Pond Wastewater

Pond water of silver catfish (Pangasius sp) has high color value, turbidity, and organic compound with the color concentration 250 Pt-Co, turbidity 13.5 NTU, and organic concentration 197.56 mg/L. High concentration of color, turbidity, and organic compound in pond water of silver catfish caused the water should be treated. One of the treatment method is chemical treatment with coagulation-flocculation method. Pond water of silver catfish was treated into clean water using powder of Moringa seed (Moringa oleifera) as organic coagulant using coagulation-flocculation method with Jar-Test system. The aim of this research is to purify water with knowing the removal efficiency of color, turbidity, and organic compound by treating pond water of silver catfish using coagulation-flocculation method and determining optimum dose of coagulant. Jar-Test result showed the color removal efficiency as 86.00% in day 1; 90.75% in day 2; and 88.77% in day 3 with 60 ppm as optimum dose. Turbidity removal efficiency was 84,52% in day 1 and 87.80% in day 2 with 60 ppm as optimum dose. Organic compound removal efficiency was 73.87% in day 1; 77.13% in day 2, and 77.29% in day 3 with 60 ppm as optimum dose.

Pulsed Light Application for Campylobacter Control on Poultry Meat and Its Effect on Colour and Volatile Profile.

Campylobacter on poultry meat needs to be controlled to reduce the risk of infection caused by the consumption of chicken meat. Pulsed light (PL) application on poultry meat was studied to control Campylobacter spp. The effect of this technology was evaluated regarding poultry meat colour and volatile compound changes. Two breast sample groups were prepared: inoculated with Campylobacter (107 bacteria of Campylobacter jejuni strains) and not inoculated. Samples were submitted to PL, five pulses/s of 300 ms, 1 Hz, and 1 J/cm2 in the apparatus, PL Tecum unit (Claranor). A response surface experimental design was applied regarding the factors of voltage (1828 to 3000 W) and distance to the source UV lamp (2.6 to 5.4 cm). The binomial factorial treatment (voltage and distance) with PL induced different energy doses (fluence J/cm2) received by samples, 2.82 to 9.67 J/cm2. Poultry meat pulsed light treated had a significant decrease of Enterobacteriaceae counts. The treatments applied were unable to reduce 1 log Campylobacter cfu/g of poultry meat. The poultry meat PL treated became slightly light, redder, and yellower than those not treated. PL can decrease the proportion of aldehydes on total volatiles in meat, particularly on those associated with chicken-like, chicken skin-like, and sweet odour notes in fresh poultry meat. Further studies of PL with higher energy doses will be necessary to confirm if there are Campylobacter reductions and about poultry meat treated under storage to evaluate if volatile compounds can affect the flavour of PL-treated meat samples.

Wild Chrysanthemums Core Collection: Studies on Leaf Identification

Wild chrysanthemums mainly present germplasm collections such as leaf multiform, flower color, aroma, and secondary compounds. Wild chrysanthemum leaf identification is critical for farm owners, breeders, and researchers with or without the flowering period. However, few chrysanthemum identification studies are related to flower color recognition. This study contributes to the leaf classification method by rapidly recognizing the varieties of wild chrysanthemums through a support vector machine (SVM). The principal contributions of this article are: (1) an assembled collection method and verified chrysanthemum leaf dataset that has been achieved and improved; (2) an adjusted SVM model that is offered to deal with the complex backgrounds presented by smartphone pictures by using color and shape classification results to be more attractive than the original process. As our study presents, the proposed method has a viable application in real-picture smartphones and can help to further investigate chrysanthemum identification.

Characterization of the Key Aroma Volatile Compounds in Nine Different Grape Varieties Wine by Headspace Gas Chromatography-Ion Mobility Spectrometry (HS-GC-IMS), Odor Activity Values (OAV) and Sensory Analysis.

During this study, the physicochemical properties, color, and volatile aroma compounds of the original wines produced from the grape varieties ‘Hassan’, ‘Zuoshaner’, ‘Beibinghong’, ‘Zuoyouhong’, ‘Beta’, ‘Shuanghong’, ‘Zijingganlu’, ‘Cabernet Sauvignon’, and ‘Syrah’ were determined and sensory evaluation was performed. Results indicated that ‘Hassan’ contained the most solids, ‘Zuoshaner’ produced the most total acid, residual sugar, total anthocyanin, and total phenol, and ‘Shuanghong’ produced the most tannin. Calculation of the chroma and hue of the wines according to the CIEL*a*b* parameters revealed that the ‘Cabernet Sauvignon’ wines were the brightest of the nine varieties and that the ‘Zuoshaner’ wines had the greatest red hue and yellow hue and the greatest saturation’. A total of 52 volatile compounds were identified and quantified in nine wine samples by HS-GC-IMS analysis, with the most significant number of species detected being 20 esters, followed by 16 alcohols, 8 aldehydes, four ketones, one terpene, and one furan, with the highest total volatile compound content being ‘Beta’. A total of 14 volatile components with OAV (odor activity value) >1 were calculated using the odor activity value (OAV) of the threshold of the aromatic compound, and the OPLS-DA analysis was performed by orthogonal partial least squares discriminant analysis (OPLS-DA) using the OAV values of the compounds with OAV values >1 as the Y variable. The VIP (Variable Importance in Projection) values of six compounds, ethyl isobutyrate, ethyl hexanoate-D, 2-methylpropanal, ethyl octanoate, ethyl butanoate-D, and Isoamyl acetate-D, were calculated to be higher than one between groups, indicating that these six compounds may influence aroma differences. It is essential to recognize that the results of this study have implications for understanding the quality differences between different varieties of wines and for developing wines that have the characteristics of those varieties.

Improvement of Antioxidant Activity and Sensory Quality of Pagilaran’s Tea Clones Treated by Tannase

PT. Pagilaran developed five new clones named PGL 9, PGL 10, PGL 11, PGL 12, and PGL 15 for black tea. These clones can be potentially made into ready-to-drink (RTD) instant tea beverages with low antioxidant activity. Tannase is an industrial enzyme with great potential for application in the food industry used to hydrolyze gallated ester catechin in green tea. There were no findings on the effects of this enzyme treatment on the chemical composition of PT Pagilaran’s tea clones. Therefore, this study is aimed to observe the effects of tannase treatment on five clones of black tea extracts to the antioxidant activity, profile of phenolic compounds, the tea brew color, consumer acceptance, and volatile compounds. The leaves of the plucking medium were traditionally processed into black tea. Furthermore, the tea brew was added at a 100 mg/100 mL concentration and then incubated for 1 hour at 37 °C. Additional tannase increased their antioxidant activities, the gallic acid, EC, and EGC concentrations due to hydrolysis of ECG, EGCG, or their derivatives. The color of the tea brew was brighter and yellower than the untreated, but the level of consumer acceptance was still good. The profile aroma and volatile compounds showed no significant changes after enzymatic treatment.

Factorial Optimization of Ultrasound-Assisted Extraction of Phycocyanin from Synechocystis salina: Towards a Biorefinery Approach.

PC is a bioactive and colorant compound widely sought in the food, nutraceutical and cosmetic industries, and one of the most important pigments produced by Synechocystis salina. However, the general extraction process is usually time-consuming and expensive, with low extraction yields—thus compromising a feasible and sustainable bioprocess. Hence, new extraction technologies (e.g., ultrasound assisted-extraction or UAE) emerged in the latest years may serve as a key step to make the overall bioprocess more competitive. Therefore, this study aimed at optimizing the yields of phycocyanin (PC) rich-extracts of S. salina by resorting to UAE; in attempts to explore this process in a more economically feasible way; valorization of the remaining cyanobacterial biomass, via extraction of other bioactive pigments and antioxidants, was tackled within a biorefinery perspective. A two-stage extraction (using ethanol and water) was thus performed (because it favors PC extraction); other bioactive pigments, including chlorophyll a (chl a), carotenoids, and other phycobiliproteins (PBPs), but also antioxidant (AOX) capacity and extraction yields were also evaluated for their optimum UAE yields. A factorial design based on Box–Behnken model was developed; and the influence of such extraction parameters as biomass to solvent ratio (B/S ratio = 1.5–8.5 mg·mL−1), duty cycle (DT = 40–100%), and percentage of amplitude (A = 40–100%) were evaluated. The model predicted higher PC yields with high B/S ratio = 6 mg·mL−1, lower DT = 80% and an A = 100%. Classical extraction was compared with UAE under the optimum conditions found; the latter improved PC yields by 12.5% and 47.8%, when compared to freeze-thawing extraction, and bead beater homogenization-based extraction, respectively. UAE successive extractions allowed to valorize other important bioactive compounds than PC, by reusing biomass, supporting a favorable contribution to the economic feasibility of the S. salina-based process towards a biorefinery approach.

Induction of stress defense response and quality retention in minimally processed peaches through the application of gamma irradiation treatments

Consumers demand fruit and vegetable products "on the go" that maintain color, flavor, nutritional and bioactive compounds almost equal to fresh products. Irradiation represents an effective technology traditionally used in fruit and vegetable as a phytosanitary treatment to preserve food quality and safety. In the present study we evaluated the effect of gamma irradiation treatments at several doses (0, 0.1, 0.3, 1.0, 2.5 kGy) on the quality and biochemical aspects of minimally processed peaches (Prunus persica L. Batsch) with low oxygen permeability packaging. During minimal processing, peach slices were treated in an antioxidant solution containing 1 % ascorbic acid and 0.5 % citric acid for 2 min. Trays of minimally processed peaches were irradiated packed inside cardboard boxes. Changes in color, firmness and polyphenoloxidase (PPO) and peroxidase (POD) activities of peaches were analyzed at different storage times (0, 7, 14 d) at 4 °C. In addition, the stress response of plant to these treatments was assessed by using the induction of heat shock proteins (HSP) as a biochemical marker. Results show that irradiation caused no substantial changes in chromatic parameters, although an immediate reduction in firmness and POD activity was observed, proportional to the increased doses applied. In turn, PPO activity remained stable while the activity of some of its isoenzymes decreased for doses higher than 0.3 kGy. The overexpression of HSP, only detected for irradiation doses of 0.1 and 0.3 kGy, in coincidence with the best performing treatments, constitutes a relevant finding not previously reported in fruit. Therefore, low doses of irradiation promoted the physiological and biochemical defense mechanisms of the fruit. HSP could thus be used in plant tissues as a biomarker of the stress brought about by exposure to irradiation, capable of preventing physiological damage. These preliminary results suggest that irradiation treatments (up to 1.0 kGy) in combination with modified atmosphere packaging (from 19 % and 10 % O2 at 0 d to 3 % and 15 % CO2 at 14 d of storage) could render high quality peach products with an extended shelf life.

Evaluating the Impacts of Climate Factors and Flavonoids Content on Chinese Prickly Ash Peel Color Based on HPLC-MS and Structural Equation Model

Climate affects Chinese prickly ash peel color directly through temperature and illumination and indirectly influences it through its effect on flavonoid compounds. In this study, a comprehensive evaluation strategy based on high performance liquid chromatography-mass spectrometry (HPLC-MS) technology and a structural equation model was applied to evaluate the effects of climate factors and flavonoids on Chinese prickly ash peel color. There were obvious geographical variations of peel color and flavonoid compounds with an obvious east–west distribution trend which were divided into high-altitude type and low-altitude type. Through path analysis, the wind speed, temperature and annual sunshine duration were found to be the key environmental factors affecting the flavonoids content and peel color, and their direct effects were higher than their indirect effect. Based on HPLC-MS technology and a structural equation model, correlation models of climatic factors and flavonoids with peel color were established, and the factors that had greater weight on pericarp color were obtained. Our results provide experimental evidence that climate factors affect the peel color by affecting flavonoid biosynthesis and accumulation, reveal the geographical variation of peel color and flavonoid component contents in Chinese prickly ash peel, establish a quantization color method for rapid evaluation of peel quality, expand on the influence of climatic factors on flavonoids content and peel coloration and promote agricultural practice in areas with similar climatic conditions.

Effects of Convective Drying of Quince Fruit (Cydonia oblonga) on Color, Antioxidant Activity and Phenolic Compounds under Various Fruit Juice Dipping Pre-Treatments

In this study, 3 mm thick quince slices were dipped in bitter orange (BO), tangerine (Citrus deliciosa Mediterranean) (CDM), orange (O), tangerine (Citrus reticulata Owari) (CRO), pomegranate (P) juices and a non-pre-treatment (control) dried at an air temperature of 70 °C and air velocity of 1.5 m/s. According to the results of the pre-treatment trials, drying time was found to be a minimum of 121 min in pomegranate at 5 min dipping time to reach a safe moisture content of 10% (w.b.). The lowest total color change (∆E) values were observed in orange juice dipped samples (10.19). We found the highest total phenolics (TP) (16.77 mg GAE/g d.w.) in CDM, Trolox equivalent antioxidant capacity (TEAC) (32.49 µmol TE/g d.w.) in P and total flavonoid (TF) (2018.15 mg GAE/kg d.w.) in BO for 5 min dipping time values. As a result, pomegranate juice pre-treatment in all dipping times improved the biocompounds for quince slices.

Novel infrared puffing: Effect on physicochemical attributes of puffed rice (Oryza sativa L.).

The effect of novel infrared (IR) puffing and various IR powers (350, 450, and 550 Watts [W]) at various distances (10, 20, and 30 cm) on physicochemical characteristics of puffed rice (puffing properties, color, total phenolic content [TPC], antioxidant activity, peroxide value, and morphology) was investigated. By reducing the distance and increasing the IR power, the volume puffing was significantly increased (p< .05), and bulk density was significantly decreased (p< .05) but there was no significant difference in the length/breadth ratio. The IR puffing effect on color, the TPC, antioxidant activity, and food compounds' analysis through Fourier transform infrared (FTIR) spectra were significant (p< .05) during IR puffing. The scanning electron microscopy (SEM) images showed that by increasing the IR power and decreasing the sample distance from the IR source, the size of protrusions was increased (the volume of the protrusions). The maximum increase in the protrusions size was observed in 10cm distance and 550 W power of IR. This is the first report on the IR puffing of rice and according to the results, the IR puffing technology has a high efficiency at the rice puffing.

Assessment of ultrasound-assisted vacuum impregnation as a method for modifying cranberries’ quality

Combined vacuum impregnation and ultrasound was proposed as an alternative method to improve the infusion of ascorbic acid in berry fruit. The effect of ultrasound application at different stages of impregnation – vacuum, relaxation, and both stages – on the qualitative characteristics of impregnated cranberries was investigated. The quality assessment was based on porosity, color, antioxidant capacity, anthocyanin, polyphenol and structure compound content. Ultrasound-assisted vacuum impregnation contributed to higher ascorbic acid content, smaller relative color difference, and greater antioxidant properties. It was found that the degree of impregnation varies considerably and depends on the stage of using ultrasound. Due to more favorable quality attributes, the conclusion was reached that ultrasound should be applied during the relaxation stage of vacuum impregnation.

Effect of alginate-based coating charged with hydroxyapatite and quercetin on colour, firmness, sugars and volatile compounds of fresh cut papaya during cold storage

Active alginate-based coatings with quercetin glycoside and complexes of hydroxyapatite/quercetin-glycoside were used to study the shelf life of fresh cut papaya stored at 6 °C. Hydroxyapatite was used as a carrier for the release of the bioactive compound. The parameters considered affecting the quality of the fruit during storage were weight loss, color, texture, sugars and volatile compounds. Active coatings with hydroxyapatite and quercetin glycoside proved a higher capacity to slow down the degradation phenomena studied, showing less weight loss, a lower reduction in glucose and fructose, as well as better firmness, than the other samples after 14 days of cold storage. Benzyl isothiocyanate, the characteristic odor compound of papaya fruit, ranged from approximately 10.0 μg/kg in fresh cut fruit to approximately 7.50 μg/kg in samples coated by alginate with hydroxyapatite/quercetin and 3.6 μg/kg in the fresh cut papaya without coating after 14 days of cold storage. The trials also indicated greater effectiveness of alginate coatings alone and with quercetin-glucoside in preserving the color of freshly cut papaya.

Degree of maturity and dry-heat processing affect visual quality and volatile profile of roasted immature rice grains

Foods from unripe cereals, such as pepeta, i.e., a flakes prepared in Tanzania from immature rice, are popular. However, factors determining sensory quality of these immature rice flakes are inadequately characterised. In this study, grain size, colour, and volatile compounds of immature rice destined for pepeta production were investigated at different maturity stages (i.e., dough-grain, mature-grain, fully-ripe, and over-ripe) and processing conditions (i.e., roasting at 80, 100 and 120 °C, with and without prior to water-soaking for 12 h at room temperature). The highest brightness, lowest redness and yellowness values in pepeta resulted from the pounding process. About 53 volatile compounds were identified in Lawama and TXD306 variety; their concentrations decreased as grain matured except for Lawama at the mature-grain stage. Odour-active compounds such as 2-isopropyl-5-methyl-1-heptanol, butyl acetate, and butyl propionate were formed upon processing into pepeta, whereas abundant 2-pentyl-furan and 2-methoxy-4-vinyl phenol significantly increased with roasting temperature. No characteristic volatile pattern was observed to differentiate pepeta from other processed rice products. Soaking before roasting had no significant (p < 0.05) effect on grain size, colour, or volatile compounds. Degree of maturity and roasting temperature both had impact on colour and volatile compounds, and subsequent sensory quality of the pepeta product.

On the relative extraction rates of colour compounds and caffeine during brewing, an investigation of tea over time and temperature

Abstract Various beliefs are common about the extraction of soluble compounds from leaf tea, suggesting that cold brewed tea or tea brewed for a shorter time than usual may contain a higher polyphenol-to-caffeine ratio, a selling point due to the potential health benefits of polyphenolic compounds. To test these beliefs, we investigated the effect of brewing time and temperature on the colour intensity and caffeine content of the extract of one type of black tea. Results showed that the extraction of the two components of interest had different half-lives, with an initial large variation of the ratio between them rapidly reaching a quite constant value. At different temperatures, a significantly different ratio between caffeine and colour compounds was observed. Although the difference in relative concentration was small, the range of brewing temperatures tested was only 20 Kelvin, so it seems possible to increase this difference. A difference in total extraction efficiency of both components together was noted too. To effectively change the ratio of the components using the extraction time would require using accurate times of less than 3 minutes and accurate temperatures unusual in a home environment.

Solubility, acidifying power and sensory properties of fumaric acid in water, hydro-alcoholic solutions, musts and wines compared to tartaric, malic, lactic and citric acids

The lower content of organic acids in grape berries due to global warming, and therefore high pHs, is forcing winegrowers to acidify must or wine to preserve their microbiological stability and their physico-chemical equilibrium. Acidification is essential to avoid damageable consequences on the colour and the sensory quality of the wines. Of the possible modes of acidification, chemical acidification is still the most common one used by OIV country members. It consists of adding lactic, malic, tartaric or citric acids to the musts and wines. Fumaric acid, with its high acidifying power and availability on the market, could be an interesting alternative at lower cost than other acids. Very few studies describing the effects of the addition of this acid on the chemical and organoleptic quality of musts and wines have been published. The present study therefore investigated the impacts of fumaric acid - namely its solubility, acidifying power, and impacts on colour and phenolic compounds - on musts and wines in comparison to other acids. Sensory analyses were also carried out to evaluate the perception threshold of each acid in the wines and compare how the acids are perceived. Except for its low solubility, fumaric acid seems to be a good candidate for an economic alternative to wine acidification. It had the highest acidifying power and slightly affected wine chemistry and organoleptic qualities. Further studies are needed to determine the appropriate step during which this acid should be added during winemaking.

Drying Onion Slices using a Food Dehydrator

Shallots are one of the mainstay products of Demak Regency which are continuously being developed. However, the Demak Shallot Cluster faces a major obstacle, namely drying technology, which is the main cause of the decline in competitiveness, and farmers suffer huge losses. Therefore, in this study, a study of the drying of sliced shallots using a food dehydrator will be carried out. The research analysis includes (1) Drying Characteristics, (2) Drying Rate Analysis, (3) Application of Thin Layer Drying Model, (4) Rehydration Ratio Analysis, (5) Color Analysis, (6) Flavonoid and Total Phenolic Analysis, (7) Antioxidant Activity Analysis. The quality parameters of shallot products in general will follow SNI 3159-2013, this standard stipulates provisions regarding the quality, size and hygiene of shallots (Allium cepa varascalonicum) of the Alliaceae family for consumption, plus the strength of onion bulbs, identification and quantification of flavonoid compounds, and anthocyanin levels. The results showed that the moisture ratio value in equilibrium was 9.34% with the fastest drying occurring at a temperature of 60 oC , which was 0.938 g/minute. The three thin layer drying models were analyzed to determine the appropriate thin layer drying model. The Page model was chosen because it has an R value of 2 the highest is 0.9353 and the lowest RMSE and x 2 values are 0.04354 and 0.0025 3. Changes in color and bioactive compounds in the dried onion slices are caused by heat which causes damage to bioactive compounds. Based on the parameters that have been determined, a temperature of 50 o C indicates the optimum temperature for drying shallot slices.