Taste Quality Research Articles

Investigating Taste and Odour Characteristics in a Drinking Water Source: A Comprehensive 3-Year Monitoring Study.

The monitoring of drinking water quality is a vital public health concern together with taste and odour (T&O) episodes, an emerging global problem causing a loss of public trust to the quality of water. Our objective was to monitor water quality of an important drinking water source and also the production dynamics of geosmin and 2-methylisoborneol (2-MIB) which cause taste and odour problems in the lake. The trophic status of the lake was classified as mesotrophic. 2-MIB was positively correlated temperature while geosmin was positively correlated with depth. Other physicochemical parameters related with water quality did not show significant correlation with geosmin and 2-MIB. The highest 2-MIB and geosmin concentrations were detected during the thermal stratification period in 2016 and 2018 by gas chromatography-mass spectrometry (GC-MS). Cyanobacteria and Actinobacteria were detected in geosmin & 2-MIB detected samples as potential taste and odour producers by PCR. Selected samples were analysed with metabarcoding and Planktothrix, Pseudanabaena, Cyanobium, Streptomyces, and Nocardioides were detected as potential geosmin & 2-MIB producers. Micrococcus, Rhodococcus, Acinetobacter, Comamonas, Novosphingobium, Sphingopyxis, Pseudomonas, Sphingomonas, Stenotrophomonas and Flavobacterium were identified as potential geosmin & 2-MIB degraders. The results highlighted the significant role of the autochthonous bacterial community, temperature and thermal stratification in the taste and odour dynamics of a drinking water source.

Interspecific hybridization and cell engineering of lettuce (Lactuca L.)

Lactuca sativa L. is a leafy vegetable crop of the Asteraceae family, widely cultivated throughout the world. The main breeding trends for lettuce include higher yields, better taste quality, earliness, and resistance to abiotic and biotic stressors. Some wild Lactuca spp. have actively been employed by lettuce breeders as donors of resistance to various diseases. Conventional and biotechnological breeding methods are both currently used to develop new lettuce cultivars. This is an overview of the main advances in the production of interspecific Lactuca hybrids, including the use of cell and tissue culture techniques, and genetic engineering. Studying artificial hybridization and natural populations makes it possible to identify evolutionary relationships among various Lactuca spp. Somatic hybridization is an overlooked but promising technology in Lactuca breeding: it allows a breeder to obtain a wider range of variations, and is beyond the strict control by GMO laws. This technique faces problems associated with complicated protoplast regeneration and the loss of reproductive ability in hybrids. Genome-editing methods are more effective and better controllable, but society is still wary of any interference with the plant genome and legally regulates the sale of GM products as food. Thus, researchers are challenged with the task to improve these techniques.

Isolation and identification of epiphytic Pichia kudriavzevii from loquat peels and investigation of its fermentation characteristics for liquor production.

During the process of fruit wine production, yeast plays a crucial role in influencing the taste, flavor, and overall quality of the wine. This study aims to enhance the flavor and quality of loquat wine by isolating strains of Pichia kudriavzevii (P. kudriavzevii) with desirable winemaking characteristics from loquat fruit fermentation broth. A total of 12 strains of P. kudriavzevii were isolated and subjected to morphological and molecular biological identification. Their fermentation performance, ethanol production, ester production, hydrogen sulfide production, killer activity, and tolerance were evaluated. The results revealed that strains Q-2, Q-9, Q-10, Q-12, Q-20, and Q-42 exhibited robust growth and strong tolerance under conditions of 40°C temperature, 12% ethanol concentration, 350g/L glucose concentration, and pH 2.8. Strain Q-42 demonstrated the strongest gas production capacity, killer activity, and good ester and ethanol production. As a highly active fermentation strain with excellent wine making characteristics, P. kudriavzevii Q-42 provides a valuable yeast resource for the industrial production of loquat wine and offers technical support for improving the overall quality of loquat wine.

Physicochemical Analysis, Antioxidant Activity, and Sensory of Sungkai (Peronema canescens Jack.) Leaf Extract

Sungkai leaves were widely used as an immunomodulatory agent during the COVID-19 pandemic. This research aimed to determine the color, phytochemical characteristics, vitamin C content, polyphenol content, antioxidant activity, and sensory of sungkai leaves extracts from various types of leaves (shoot, young, and old) as well as the condition (fresh and dry). The extraction process included boiling the sample with water at a temperature of 90⁰C for 10 minutes. The parameters observed in this study were color, phytochemicals screening, vitamin C, polyphenols, antioxidant activity, and sensory. The results showed that the extract color was influenced by the types of leaves. These included red-purple for the shot leaves and yellow for young and old leaves. The extract contained flavonoids, tannins, and saponins. The fresh leaves extract produced a higher total vitamin C, polyphenols, and antioxidant activity compared to the dry counterparts. Furthermore, the highest chemical content of sungkai leaves extract was discovered in fresh shoot leaves with total vitamin C, polyphenols, and IC50 values of 172.77 μg/ml, 280.77 μg/ml, and 28.33 μg/ml (strong antioxidant activity), respectively. Sensory characteristics of color, aroma, taste, and overall taste in each extract differed in liking score. Overall, panelists preferred the extract from dried older leaves.

Innovative Pathogen Reduction in Exported Sea Bass Through Atmospheric Cold Plasma Technology.

The safety of sea bass is critical for the global food trade. This study evaluated the effectiveness of atmospheric cold plasma in reducing food safety risks posed by Salmonella Enteritidis and Listeria monocytogenes, which can contaminate sea bass post harvest. Cold plasma was applied to inoculated sea bass for 2 to 18 min, achieving a maximum reduction of 1.43 log CFU/g for S. Enteritidis and 0.80 log CFU/g for L. monocytogenes at 18 min. Longer treatments resulted in greater reductions; however, odor and taste quality declined to a below average quality in samples treated for 12 min or longer. Plasma treatment did not significantly alter the color, texture, or water activity (aw) of the fish. Higher levels of thiobarbituric acid reactive substances (TBARSs) were observed with increased exposure times. Cold plasma was also tested in vitro on S. Enteritidis and L. monocytogenes on agar surfaces. A 4 min treatment eliminated the initial loads of S. Enteritidis (2.71 log CFU) and L. monocytogenes (2.98 log CFU). The findings highlight the potential of cold plasma in enhancing the safety of naturally contaminated fish. Cold plasma represents a promising technology for improving food safety in the global fish trade and continues to be a significant area of research in food science.

Research Progress on the Mechanism of the Impact of Myofibrillar Protein Oxidation on the Flavor of Meat Products.

Myofibrillar proteins primarily consist of myosin, actin, myogenin, and actomyosin. These proteins form complex networks within muscle fibers and are crucial to the physical and chemical properties of meat. Additionally, myofibrillar proteins serve as significant substrates for the adsorption of volatile flavor compounds, including aldehydes, alcohols, ketones, and sulfur and nitrogen compounds, which contribute to the overall flavor profile of meat products. A series of chemical reactions occur during the processing, storage, and transportation of meat products. Oxidation is one of the most significant reactions. Oxidative modification can alter the physical and chemical properties of proteins, ultimately impacting the sensory quality of meat products, including flavor, taste, and color. In recent years, considerable attention has been focused on the effects of protein oxidation on meat quality and its regulation. This study investigates the impact of myofibrillar protein oxidation on the sensory attributes of meat products by analyzing the oxidation processes and the factors that initiate myofibrillar protein oxidation. Additionally, it explores the control of myofibrillar protein oxidation and its implications on the sensory properties of meat products, providing theoretical insights relevant to meat processing methods and quality control procedures.

Pengaruh Cita Rasa dan Kualitas Pelayanan Terhadap Kepuasan Pelanggan Pada PT.XYZ Depok

XYZ (Company name disguised at the request of the company) is a well-established bakery industry in Indonesia. In running its business, of course, the company not only provides quality products and taste, but also provides good service quality because it can increase customer satisfaction. The purpose of this study is to determine the influence of taste and service quality on customer satisfaction of PT. XYZ Depok. The research method used is quantitative statistics. The population of this study is consumers who buy PT. XYZ Depok. Data collection methods with interviews, documentation, and questionnaires. Data processing using SPSS 25 with multiple linear regression analysis technique. Based on the results of the study, it was shown that taste had a significant effect on customer satisfaction and service quality also had a significant effect on customer satisfaction at PT. XYZ Depok, then the taste and quality of customers simultaneously have a significant effect on customer satisfaction at PT. XYZ Depok.

Palatability of organic acids and their derivatives for cichlid fishes (Cichlidae)

Taste attractivity of 15 organic acids and their derivatives (ascorbic, citric, sorbic, malic, oxalic, acetic, glycolic, α- and γ-aminobutyric acids, their Na+- and K+-salts; 0,1 M) was compared for 5 species of cichlid fishes (Cichlidae) – Nile Oreochromis niloticus and Mozambique O. mossambicus tilapias, golden mbuna Melanochromis auratus, lemon cichlid Neolamprologus leleupi and tailbar cichlid Vieja hartwegi. Citric and oxalic acids, Na+-ascorbate, K+-sorbate and K+-citrate, ammonium oxalate have an attractive or indifferent taste for fish, ascorbic and sorbic acids, Na+-citrate and Na+-malate have an aversive or indifferent taste. Malic acid has an attractive taste for tailbar cichlid, an aversive taste for Mozambique tilapia and an indifferent taste for other cichlids. Acetic acid and isomers of aminobutyric acid have indifferent taste for all fishes. The taste attractivity of organic acids may be different compared to salts formed on their basis. The attractiveness of salts is higher than that of the corresponding acids in 10 out of 28 cases, lower in 4 cases, and the same in 14 cases. The conversion of ascorbic and sorbic acids into Na+ and K+ salts is accompanied by an increase in taste attractivity in most cichlids, malic acid to malate Na+ – in half of the species. For most fish, citric acid and its Na+- and K+-salts have similar attractiveness. Oxalic acid, compared with ammonium oxalate, has a higher attractiveness for lemon cichlid, a lower one for Mozambique tilapia and the same taste quality for the other three fish species. There are no differences between the consumption of agar pellets with isomers of aminobutyric acid and pellets with acetic and glycolic (hydroxy acetic) acids in all cichlids. The feeding behavior shown by cichlids during the orosensory testing of pellets is similar – fish perform a small number of rejections and repeated grasps of pellets, the duration of pellet retention time in the oral cavity is similar.

Deciphering Peripheral Taste Neuron Diversity: Using Genetic Identity to Bridge Taste Bud Innervation Patterns and Functional Responses.

Peripheral taste neurons exhibit functional, genetic, and morphological diversity, yet understanding how or if these attributes combine into taste neuron types remains unclear. In this study, we used male and female mice to relate taste bud innervation patterns to the function of a subset of proenkephalin-expressing (Penk+) taste neurons. We found that taste arbors (the portion of the axon within the taste bud) stemming from Penk+ neurons displayed diverse branching patterns and lacked stereotypical endings. The range in complexity observed for individual taste arbors from Penk+ neurons mirrored the entire population, suggesting that taste arbor morphologies are not primarily regulated by neuron type. Notably, the distinguishing feature of arbors from Penk+ neurons was their propensity to come within 110 nm (in apposition with) different types of taste-transducing cells within the taste bud. This finding is contrary to the expectation of genetically defined taste neuron types that functionally represent a single stimulus. Consistently, further investigation of Penk+ neuron function revealed that they are more likely to respond to innately aversive stimuli -sour, bitter and high salt concentrations - as compared to the full taste population. Penk+ neurons are less likely to respond to non-aversive stimuli -sucrose, umami, and low salt- compared to the full population. Our data support the presence of a genetically defined neuron type in the geniculate ganglion that is responsive to innately aversive stimuli. This implies that genetic expression might categorize peripheral taste neurons into hedonic groups, rather than simply identifying neurons that respond to a single stimulus.Significance Statement Peripheral taste neuron coding has been heavily debated. Our study delves into this issue by leveraging genetic expression in a specific neuron subset to relate peripheral innervation patterns to functional taste responses. We examined a taste neuron type that appears to be in apposition with multiple taste-transducing cell types and responds to innately aversive concentrations of sour, bitter, and high NaCl stimuli. These collective observations suggest that genetic markers can delineate groups of neurons sharing similar hedonic responses rather than categorizing neurons solely based on individual taste qualities.

Quality diversity of three calcium-rich Primulina vegetables: A comprehensive analysis of calcium content, metabolite profiles, taste characteristics, and medicinal potential

Primulina plants native to karst regions are exceptionally rich in calcium and have been developed into high‑calcium leafy vegetables. However, limited knowledge of their metabolites, taste characteristics, and potential medicinal value restricts further genetic improvements. This study conducted a comprehensive analysis on three breeding species of Primulina vegetables. Common garden experiment demonstrated significant calcium enrichment capability, with calcium content ranging from 204.45 to 391.52 mg/100 g. Through widely-targeted metabolomics, 1121 metabolites were identified within these Primulina vegetables. Furthermore, comparative analysis identified 976 differentially accumulated metabolites across nine comparison groups, driven mainly by flavonoids, phenolic acids, and lipids. Integration of electronic tongue analysis and metabolomics revealed taste profiles and identified 17 key candidate compounds related to taste. Based on network pharmacology analysis, 32 active ingredients were found in Primulina vegetables, which highlighted potential medicinal value. These findings provide a data-driven foundation for breeding programs aimed at enhancing nutritional and flavor traits.

Improvement in Taste Quality of Rice Porridge Using Konjac Glucomannan.

Improving the taste quality of rice porridge in a scientific way is essential to guiding residential and commercial production. This study aimed to determine the impact of konjac glucomannan (KGM) on the taste quality of rice porridge. The obtained results showed that the optimal concentration of KGM added to rice porridge is 1%. This was primarily observed via the reduction in water absorption, swelling power, and iodine blue value, thus increasing the hardness of rice porridge. At the same time, KGM also reduced the free water content and improved the water-holding capacity of rice porridge. Nevertheless, the pasting properties showed that the high viscosity of KGM raised the pasting viscosity of rice flour, thereby enhancing the stickiness of rice porridge with the increase in the KGM concentration. In addition, KGM gave the rice porridge a stronger aroma. Sensory evaluations further confirmed significant improvements in the color, odor, palatability, and overall acceptability of KGM-supplemented rice porridge (p < 0.05). To summarize, adding an appropriate amount of KGM was beneficial in forming a richer flavor and improving the taste quality of rice porridge. The findings offer valuable insights into the scientific processing of rice porridge products.

Evaluation of commercial and taste qualities of plum fruits in the foothills of Kabardino-Balkaria

Breeding varieties with high commercial and consumer qualities of fruits is one of the priority areas in the selection and variety study of domestic plum. Accordingly, the evaluation of some commercial and consumer qualities of fruits in plum varieties in the specific conditions of the mountains and foothills of the region is of great practical and scientific interest. Taking into account market requirements and the growth of consumer demand for fruit products, it is necessary to constantly update the range of plums. In this regard, varieties and hybrid forms of European plum for the subsequent selection of variety samples with high commercial characteristics have been studied (fruit weight, their uniformity and shape, cover color, aroma, pulp juiciness, taste, etc.). As a result of the studies, variety samples with the best commercial and taste properties of fruits have been selected. The following varieties have been distinguished by a high sugar content: Čačakska rannyaya - 18.8%, Grosso de Felicio - 16.5%, Big Heart - 14.7%, Milena - 13.8%, Velikiy Gertsog - 12.7%. The following varieties have been noted for the content of organic acids: Big Heart - 1.31%, Velikiy Gertsog - 1.1%, Milena - 0.92%, Čačakska rannyaya - 0.9%, Grossa de Felicio - 0.89%. Vitamin C is found in the highest amounts in the fruits of the following varieties: Big Heart – 7.85%, Grossa de Felicio – 6.34%, Angelina – 6.2%, Kyrgyzskaya Prevoskhodnaya – 5.34%. The size of the fruit is one of the characteristic varietal properties, despite the fact that it is largely determined by the cultivation conditions, the agricultural technology used, the age of the plant, its crop load, the variety-rootstock combination, as well as a number of other circumstances. The highest fruit weights are shown by the following varieties: Big Heart - 39.1 g, Kyrgyzskaya Prevoskhodnaya - 46.3 g, Zheltaya Afaska - 53.3 g, Zheltaya Large - 56.0 g, Kabardinskaya Rannyaya - 59.0 g, Fortuna - 65.1 g, Black Star - 78.7 g, Byron Gold - 84.2 g, Grossa de Felicio - 85.3 g, Angelina - 87.0 g, Ti Chi San - 97.1 g, Burbank Giant - 120.0 g.

Utilizing nontargeted metabolomics integrated with quality component quantitation via differential analysis to reveal the taste differences between and metabolite characteristics of hawk black tea and hawk white tea

This study conducted a comprehensive analysis of the differences in the taste characteristics of hawk black tea and hawk white tea, exploring the intrinsic relationship between nonvolatile metabolites and these taste characteristics. The results revealed significant differences in taste properties of the two types of hawk tea. Hawk black tea mainly exhibits a fresh, sweet, and sweet aftertaste quality, whereas hawk white tea offers a mellow and pure taste. Comparative analysis revealed that the content of amino acids and carbohydrates in hawk black tea was significantly higher than that in hawk white tea, while the content of flavonoids and organic acids was relatively lower. Quality composition results indicated significant differences in the 13 major quality components and water extracts between the two hawk teas, aligning with the quantitative descriptive analysis results. Additionally, through weighted gene coexpression network analysis, significant associations were found between 671 metabolites across 155 metabolic pathways and 9 taste characteristics. Among them, flavonoid biosynthesis and degradation are the main metabolic pathways of the two types of hawk tea. And it was found that butin, phlorizin, naringin, dihydrokaempferol, sakuranetin, apigenin, (−)-epicatechin, (+)-gallocatechin, caffeoyl shikimic acid, homoeriodictyol, which are 10 flavonoids, are the key metabolites affecting the taste difference of hawk black and white tea. Additionally, this study found that hawk tea does not contain caffeine, which is of great significance for the development of caffeine-free beverages in the future.

Different taste map for amiloride sensitivity, response frequency, and threshold to NaCl in the rostral nucleus of the solitary tract in rats.

Studies on taste bud cells and brain stem relay nuclei suggest that alternative pathways convey information regarding different taste qualities. Building on the hypothesis that amiloride (epithelial Na channel antagonist)-sensitive neurons respond to palatable salt (low-concentration) and amiloride-insensitive neurons respond to aversive salt (high-concentration), we investigated the histological distribution of taste-sensitive neurons in the rostral nucleus of the solitary tract in rats and their NaCl and amiloride sensitivities. We recorded neuronal activity in extracellular single units using multi-barrel glass micropipettes and reconstructed their locations on the rostrocaudal and mediolateral axes. Seventy-three taste-sensitive neurons were categorized into the best-taste category. The amiloride sensitivities of the 31 neurons were examined for 0.1, 0.2, 0.4, and 0.8 M NaCl. The neuronal distribution of amiloride-sensitive neurons was located in the lateral region, while amiloride-insensitive neurons were located in the medial region. The amiloride-sensitive neurons responded to low salt concentrations, signaling the NaCl levels required by body fluids. Amiloride-insensitive neurons were silent at low salt concentrations but may function as warning signals for high salt concentrations. Low-threshold and/or high-response neurons were located in the rostrolateral region. In contrast, high-threshold and/or low-response neurons were located in the caudal-medial region.

Biochemical characteristics of some varieties of peach and nectarine grown in Sochi

Biochemical characteristics and features of the most promising varieties of stone fruit crops (peach, nectarine) submitted for research have been shown. Biochemical analyzes of peach and nectarine fruits grown in the humid subtropics of Russia were carried out in 2019-2020 at the Subtropical Scientific Center of the Russian Academy of Sciences in the Laboratory of Plant physiology and Biochemistry. The following varieties were used for biochemical analyzes: Rannyaya zarya, Larisa (control one), Osenniy rymyanets, Anton Chekhov, Big Top, Nectarine Sklor. The content of biologically valuable substances in stone fruits, which determine not only their taste characteristics, but also their nutritional and therapeutic and prophylactic effects, is a criterion for high commercial quality of products. That is why we are faced with the task of assessing the chemical composition of peaches and nectarines, which directly depends on weather and climate conditions, varietal characteristics, place of growth, etc. It is known that the pulp of peaches and nectarines contains a large amount of sugars, organic acids (mainly malic), vitamins, enzymes, macro- and microelements. In assessing the taste qualities of peaches and nectarines, the content of sugars, acids and vitamin C (or ascorbic acid), which acts as an antioxidant, is of great importance. Biochemical analysis of peach and nectarine fruits revealed the maximum sugar content - 10.16% in the Larisa variety (control one) of mid-late ripening period, the minimum in the Rannyaya Zarya variety of early ripening period, which is significantly lower by 1.3 times compared to the control one. High vitamin C content in the Larisa variety fruits was noted - up to 16.56 mg%, which is significantly higher than other studied varieties by 2.60-5.19 mg%. Promising varieties Larisa and Anton Chekhov were distinguished by a balanced taste of fruits and resistance to abiotic factors of the environment of the Black Sea coast of Russia.

Analysis of free amino acids and evaluation of the quality of gallnut honeys from different geographical areas

AbstractGallnut honey, a typical Chinese medicinal commodity, is produced from the nectar of Rhus chinensis Mill. Gallnut honey is very popular with consumers because of its health effects and nutritional value, but its specific nutritional composition and medicinal components are not clear. Free amino acids are important nutritional components of honey, and can provide relevant information about the honey, such as geographical and botanical origin, as well as adulterations. The aim of this paper was to explore the free amino acid characteristics of gallnut honeys in different areas. 18 free amino acids from 17 places in China were determined by automatic amino acid analyser analysis, and the geographical characteristics were studied by principal component analysis and cluster analysis. Results showed that gallnut honey is rich in free amino acids. A total of 12 types of free amino acids were detected in all honey-producing areas, and the total amino acid content was 0.132–0.292 g/100 g. Due to its free amino acid content gallnut honey has high nutritional supplement potential, and exhibits good pharmacodynamic activity and special taste characteristics. Flavour-related free amino acids were primarily aromatic free amino acids and umami free amino acids. Pharmacodynamic free amino acids accounted for 61.22–83.85%. Results also showed that free amino acids contribute to the geographical tracing of honey, and samples of gallnut honey at different altitudes can be distinguished by cluster analysis.

Seasonal and inter-species variations in nutrient components and taste characteristics of farmed scallops from Northern China

Scallops are considered a healthy seafood due to their abundant nutrition and pleasant taste. However, the biochemical composition of scallops harvested in different seasons varies, which affect their quality. To identify the superior breeding species and optimal harvesting time, the seasonal- and species-specific variations in nutrient and flavor components were investigated for two species of scallops (Chlamys farreri and Patinopecten yessoensis) using accredited methods. Regarding seasonality, the levels of proteins, fat, fatty acids, and water-soluble vitamins were significantly higher in summer. Both species of scallop had superior taste in summer and spring. Conversely, winter scallops had a healthier proportion of unsaturated fatty acids for humans, as well as richer fat-soluble vitamins. As for species differences, C. farreri exhibited higher protein proportion and vitamin B5 content, while P. yessoensis exhibited more fat and essential amino acids. Flavor indexes suggested that P. yessoensis was more delicious than C. farreri in the same season. Overall, a comprehensive assessment of the nutritional quality of scallops, using the integrated biomarker response (IBR) index, revealed that marketable scallops in early summer and late spring exhibited better quality, and P. yessoensis scored higher than C.farreri in terms of nutrition and taste.

Special Issue: ‘Advanced Studies in Maintaining Post-Harvest Quality of Fruits and Vegetables’

The characteristics of taste, flavor, nutrition, and safety in fruits and vegetables during post-harvest, minimal processing, fresh-cutting, fermenting, and processing are critical elements in the storage and sale of products [...]

Characterization of Robusta Coffee Powder with Addition of Palm Sugar and Vanilla Powder to Improve The Quality of Robusta Coffee (Coffea canephora Pierre)

Bondowoso Robusta Coffee is a type of Robusta coffee that has a distinctive taste and high quality. The distinctive taste and high quality are obtained from the results of harvest management and post-harvest processing in accordance with Standard Operating Procedures (SOP). This research will be carried out by testing the characteristics of Robusta ground coffee with a mixture of palm sugar and vanilla flavoring to improve the quality of Robusta ground coffee. This was done by knowing the physicochemical and organoleptic properties of the mixed Robusta ground coffee. The aim of this research is to determine the interaction between roasting level and the composition of palm sugar and vanilla powder on the physiochemical and organoleptic properties of 3 in 1 Robusta Coffee. This research uses an experimental plan arranged factorially with the basic pattern of a Completely Randomized Design (CRD) with 4 replications. This design has two factors, the first factor is the roasting level and the second is the mixture composition. The results of this research show (1) The interaction of Roasting Level and Mixture (palm sugar and vanilla powder) has no significant effect on all observed variables such as water content, Brix content, pH value, and powder bulk density. (2) The effect of the main level of roasting has a very significant effect on the observed variables of rainfall density and an insignificant effect on the variables of air content, Brix content and pH value. (3) The effect of the main mixture has a very significant effect on the observed variables of air content, Brix content and powder bulk density and has no significant effect on the variable pH value.

Effect of the Fermentation Time of Purple Sweet Potato (Ipomea Batatas L) Synbiotic Yoghurt with Probiotic Starter on Product Quality and Antioxidant Activity

Purple sweet potato (Ipomea batatas L) has the potential as a fermentation medium because it has a high carbohydrate content of around 20.1%. The combination of purple sweet potato extract, skimmed milk, and probiotic starter is expected to be a synbiotic yogurt that can help the digestive system. This study aims to determine the effect of long-term fermentation of purple sweet potato synbiotic yogurt with probiotic starter culture on product quality and antioxidant activity. The observed quality was chemical, microbiological, and organoleptic, with variations in fermentation time of 0, 4, 8, and 12 hours. The study's results showed a long-term effect of the fermentation of purple sweet potato synbiotic yogurt with probiotic starter culture on the quality of yogurt. The variation of 0-hour fermentation time did not meet the pH chemical quality standard with a value of 5.16. Still, it met the TAT chemical quality standard with a value of 0.513%, while the variation of fermentation time of 4-12 hours met the pH quality standard with a value of 3.88-4.33 and a TAT of 1.268-1.967%. In the quality of microbiology, there was a total increase in BAL, which was 46.2×107 - 90.61×107. The best organoleptic quality of color, taste, and aroma was obtained in the 8-hour fermentation variation, while the best texture organoleptic quality was obtained in the 12-hour fermentation variation. The best antioxidant activity was received at 12 hours of fermentation with an IC50 value of 62.727 ppm. From this study, it can be concluded that the best yogurt results are obtained with a fermentation time of 12 hours.