Acid Taste Research Articles

Successful combination of lactic acid bacteria and yeast fermentation and enzymatic treatment to re-cycle industrial bread by-products for bread making

Bread industry generates significant amounts of by-products which are discarded every day with relevant economic and environmental repercussions, despite they still contain high concentrations of potentially exploitable nutrients. Aiming to develop new sustainable solutions, this study explored the synergistic application of enzymatic treatment and sourdough fermentation to re-cycle industrial bread by-products for new sourdough bread making. Lactiplantibacillus plantarum SD69. B2 and Saccharomyces cerevisiae SD69. E3 were used as starters, while α-amylase, amyloglucosidase and protease were assessed for their ability to hydrolyze starch and proteins, providing more available carbon and nitrogen sources for the microorganisms. The bread waste-based sourdoughs made by combining protease and L. plantarum SD69. B2 alone or in combination with S. cerevisiae SD69. E3 were selected based on acidification and growth kinetics, and their biochemical, amino acid, and peptide profiles were also characterized demonstrating promising properties. Therefore, they were used, at different percentages, for bread making. Although a slightly acidic pH and a low leavening power, due to the denatured proteins and gelatinized starch in the bread by-products, the texture and sensory analyses of new breads revealed better textural attributes, smell, acidic taste, and overall acceptability compared to the control. The possible reasons behind such features were discussed. The overall results demonstrated that the approach proposed in this study was effective to valorize bread by-products, and it represents a starting point to develop strategies responding to the current perspective of circular economy in food industry.

Common Voice Disorders among Bus Helpers in Dhaka City

Background: There are approximately 9911 buses and 8515 minibuses are running within Dhaka city. Most of them have bus helpers who most of the time uses loud voice and yelling for their job. For which they are under a great risk of having voice disorder. No study was conduct to find the rate of voice disorder in this group. This study will seek out the rate of voice disorder and the risk among this group. Materials and methods: A total of 80 bus helpers participated in the study. Their vehicle routes were within Dhaka city. It was a cross-sectional survey. Sampling was done by convenience technique. Samples were selected from different bus depots in Dhaka city. Data were collected by face to face interview using a questionnaire. Data analysis was done by descriptive statistical analysis. Statistical Package for Social Science- 17 (SPSS) and Microsoft Excel 2007 were used for data analysis. Results: The result shows that 84% of bus helpers had voice problem throughout their carrier. Current symptoms present among them are hoarseness (92%) vocal fatigue (73%), pain in throat (58%), constant throat dryness (67%) and frequent throat clearing (48%). Less frequent symptoms are breathy voice, strained voice, monotone voice, sore throat, acid taste and loss of voice. Only risk factor found is not drinking adequate water. Conclusion: The study reveals that different types of Vocal disorders are very common among the bus helpers. So, preventive measures and education are necessary to get rid of this problem. IAHS Medical Journal Vol 7(1), June 2024; 60-64

A clinical study on the efficacy and safety of poly-herbal formulation in managing functional dyspepsia

IntroductionFunctional dyspepsia is a common condition that affects millions of people worldwide. It is characterized by symptoms such as abdominal discomfort, bloating, and nausea, which can significantly impact a person's quality of life. While there are several pharmaceutical treatments available, many individuals are turning to herbal remedies as a safer and more natural alternative. This clinical study aimed to evaluate the efficacy and safety of poly-herbal formulation (PHF), marketed under brand names like Dizester® Herbal, Great Day®, etc. in patients suffering from functional dyspepsia compared to Pantoprazole, a commonly used pharmaceutical treatment. Materials & MethodsThe study included 80 patients, with 40 patients in each treatment arm. The primary objective was to assess the improvement in symptoms using various questionnaires at All India Institute of Medical Science Bhubaneswar, including the Reflux Disease Questionnaire, Short-Form Leeds Dyspepsia Questionnaire, GERD-Health Related Quality of Life Questionnaire, visual analogue scale (VAS) for pain, and Investigator's Symptomatic Assessment. The secondary objective was to evaluate the safety of PHF by assessing liver and renal function parameters and hemogram. Results & discussionThe results showed significant improvement in symptoms of GERD in the PHF group, which was comparable to the Pantoprazole group. The burning feeling behind the breastbone, pain behind the breastbone, burning feeling in the center of the upper stomach, acid taste in the mouth, and unpleasant movement of material upwards towards the mouth improved significantly from the beginning of the study to the follow-up visits. The mean VAS score reduced by 71.5 % in the PHF arm and 67.85 % in the Pantoprazole arm. Additionally, the study found no abnormal elevations in liver and renal function parameters in blood or any abnormal changes in hemogram, indicating the safety for use in patients with functional dyspepsia. Since the synthetic anti-dyspeptic drugs like proton pump inhibitors are known to have adverse effects, this natural alternative PHF shows promising results in a safer way. ConclusionIn conclusion, this study provides evidence for the efficacy and safety of PHF in improving symptoms of functional dyspepsia. The use of synthetic anti-dyspeptic medications has been associated with the occurrence of undesirable effects. In light of this, PHF has demonstrated encouraging outcomes in a manner that is considered safer.

Is aquafaba suitable as a coffee creamer and foam enhancer in instant coffee?

Coffee is commonly consumed with a creamer to reduce the acidic taste, and rich foam is an important feature, particularly in instant coffee. We examined two aquafaba (AF) powders, chickpea and navy bean, as coffee creamers and foam enhancers using physical, chemical, and LC-Q-Orbitrap High-Resolution Mass Spectrometry methods. Chickpea AF powder contained more protein and phenolic content than navy bean AF, while the latter exhibited greater pH, total sugars, saponin, and ash levels. Navy bean AF also showed better flowability and solubility than that of chickpea, hence worse hygroscopicity. Interestingly, adding either AF powder to instant coffee (1 % dw/v) increased protein by 15 % and phenolic content by 4.23 %, but not whiteness. The LC-Q-Orbitrap analysis elucidated their foam properties. Coffee-added chickpea AF foams are better than free coffee and navy bean AF, although the latter's foam is more stable. Thus, AF can enhance coffee froth not act as a whitening agent.

Association of oral manifestations with severity of the disease in ulcerative colitis patients

ObjectiveInflammatory bowel diseases (IBD), such as Crohn’s disease (CD) and ulcerative colitis (UC), are chronic conditions primarily affecting the intestines. This study aims to identify the nature and frequency of oral symptoms and signs in patients with ulcerative colitis and to explore the connection between these complications and the activity of the disease.MethodsThis descriptive-analytical study involved ulcerative colitis patients who visited the gastroenterology clinic at Shahid Sayad Shirazi Hospital in Gorgan, along with an equal number of healthy companions as a control group in 2019. A gastroenterology internist assessed the disease severity through clinical examination and a simple clinical disease activity index for colitis patients. The collected data were then analyzed statistically using SPSS version 19.ResultsThe average age of patients in the case group was 41.84 ± 11.66 years, while in the control group it was 40.43 ± 12.67 years. There was a significant correlation between difficulty swallowing, burning sensation in the mouth, vomiting, acidic taste, the presence of oral ulcers, and a coated tongue with the severity of disease activity (p < 0.05). However, no significant relationship was found between other variables and the severity of disease activity (p > 0.05).ConclusionThe results of this study confirm that as the severity of ulcerative colitis increases, the occurrence of oral lesions also rises, particularly during severe disease activity. Among oral symptoms, dry mouth had the highest incidence, followed by bad breath and changes in taste. The most common oral lesions observed were a coated tongue, grooved tongue, and oral ulcers, respectively.

Exploring the Potential of Kishk-like Novel Product in Solving the Acidic Whey Conundrum in the Dairy Industry

Acidic whey, unlike sweet whey, poses significant environmental challenges in the dairy industry. The Lebanese population consumes large quantities of labneh (strained yogurt) and white cheese, resulting in substantial acidic whey production, which presents disposal issues and pollution risks. Kishk, a fermented-milk cereal mixture, has a characteristic acidic taste. This study developed a Kishk-Like product using concentrated acidic whey as a substitute for fermented milk, addressing the disposal problem while enhancing dairy industry profitability. This study was conducted from April to June 2023. As consumer acceptance is the first step in food product development, a triangle sensory test was performed three times with 30 panelists each time, who attempted to differentiate between an established fermented cow’s milk kishk (CMK) and the new Kishk-Like product (KLP) made with three-fold concentrated acidic whey. In the three runs, 11, 9 and 13 out of 30 panelists were able to differentiate between the CMK and KLP samples, yielding p-values of 0.415, 0.713 and 0.166, respectively. These findings, coupled with the fact that approximately 12 kg of acidic whey is required to produce 1 kg of KLP, highlight its potential as a straightforward, economically viable solution for the acidic whey disposal dilemma, warranting further research into its development, characterization and standardization.

Decoding the Molecular Mechanism of Sweet Taste of Amino Acids by Their Intrinsic Properties and Interactions with Human Sweet Taste Receptor

AbstractThe molecular basis of sweet taste toward various amino acids has not been fully elucidated. In this study, by correlation of their sweetness intensities with molecular properties, it is revealed that hydrophobic or dispersion force between side chains and sweet taste receptor (Tas1R2/Tas1R3) plays a prominent role for eliciting sweetness. Furthermore, the interaction modes of 13 amino acids with receptor indicate that amino (AH) and carboxyl (B) glucophores of different amino acids interact with identical residues of receptor, while the hydrophobic side chains (X glucophores) conduct distinct topological orientations with receptor, determining their chirality selection and sweetness intensities. Molecular dynamics analysis shows that sweet d‐amino acids move toward the hydrophobic transmembrane domain during activation with more contact numbers with receptor than nonsweet l‐amino acids, providing a mechanistic elucidation of previous inconsistent sensory evaluation results of specific amino acids. Moreover, by comparison with the interactions of a dipeptide sweetener, aspartame with Tas1R2/Tas1R3 and nonsweet l‐glutamate with class C G protein‐coupled receptors, we conclude that a complementary interaction mode with both hydrophilic and hydrophobic contacts accounts for the molecular origin of their sweet taste, presenting in‐depth insights and valuable guidelines for further molecular designs or modifications of amino acids‐derived sweeteners.

Sensory Characteristics Of Tamarillo (Solanum betaceum) Jam With Pectin Addition As Gelling Agent

The objective of this study is to examine the impact of adding pectin at levels of 0% (X0), 0.5% (X1), 1% (X2), and 1.5% (X3) on the color, taste, texture (soft and spreadable), and aroma of the tamarillo jam that is made. This kind of study uses a fully randomized design approach (RAL) with four treatments and three replications. It is a pure experiment. Three small panelists participated in organoleptic tests as part of this study to assess the pectin-added tamarindo jam's quality based on the method of preparation. Variant analysis (ANAVA) was used to statistically examine the collected data. The Duncan test should be performed if Fcal exceeds Ftable. The finest quality jam was produced by adding 0.5% (X1) pectin, as evidenced by the jam's crimson color (3.89), less fragrant tamarillo aroma (2.66), soft and spreadable texture (4.00), and sweet acidity taste (3.78).

Functionality, physicochemical properties, and applications of chitosan/nano-hydroxyapatite–tea polyphenol films

An active chitosan (CS) film containing a nano-hydroxyapatite–tea polyphenol (HAP-TP) complex was designed and prepared. The effects of HAP-TP loading on the structural and physicochemical properties of the CS-based film were evaluated. The mechanical and thermal properties of the film were significantly improved by the resulting intermolecular interactions and formation of hydrogen bonds between HAP-TP and CS, which reduced the water vapor and oxygen permeabilities of the film by 29.78 and 35.59 %, respectively. The CS-HAP-TP film exhibited excellent slow-release behavior and antioxidant activity, with a cumulative release rate at 700 h 6.79 % lower than that of CS-TP films. The CS-HAP-TP film significantly inhibited the deterioration of semi-dried golden pompano, and thus helped to retain the taste of umami and sweet amino acids in fish samples, while reducing off-flavor generation. The film therefore shows considerable potential as an active packaging material for the preservation of semi-dried fish products.

Comparison of Different Deodorizing Treatments on the Flavor of Paddy Field Carp, Analyzed by the E-Nose, E-Tongue and Gas Chromatography-Ion Mobility Spectrometry.

Changes in the flavor and taste profiles of Paddy Field Carp after deodorization with perilla juice (PJ), cooking wine (CW) and a mixture of the two (PJ-CW) were analyzed using the E-nose, E-tongue, gas chromatography-ion mobility spectrometry (GC-IMS), free amino acid analysis and taste nucleotide analysis. The E-nose and E-tongue revealed that deodorization reduced the content of sulfur-containing compounds, enhanced umami, bitterness, sourness and astringency, and decreased saltiness. PCA and OPLS-DA analysis successfully distinguished between the effects of the treatments. Free amino acids increased from 8777.67 to 11,125.98 mg/100 g and umami amino acids increased from 128.24 to 150.37 mg/100 g after PJ-CW deodorization (p < 0.05). Equivalent umami concentration (EUC) comparisons showed that PJ-CW treatment produced the greatest synergistic umami enhancement (to 3.15 g MSG equiv./100 g). GC-IMS detected 52 aroma compounds; PJ treatment produced the greatest diversity of aldehydes, including heptanal, nonanal, hexanal, 3-methylbutanal, (E)-2-heptenal and (E,E)-2,4-heptadienal. The total content of volatile flavor compounds was the highest after PJ-CW treatment, and the content of many characteristic flavor substances (3-hydroxy-2-butanone, benzaldehyde, 5-methyl-2(3H)-furanone) increased. These findings provided a theoretical basis for the further development of deodorization methods for Paddy Field Carp.

Monitoring the Ripening Process of Rainbow Trout Marinade Prepared in Different Acid and Salt Concentrations by Following the Changes in Physicochemical and Sensory Parameters

ABSTRACT Physicochemical and sensory changes of fish were investigated during marination of rainbow trout. Equilibration in the acidity of A (2% acid, 8% salt), B (4%, 8%), C (2%, 12%), and D (4%, 12%) groups took place at the 24, 24, 30, and 30th hours, respectively; in salt, it occurred at 36, 42, 42, and 36th hours, respectively. With ripening, a* value decreased, and b* value and hardness increased. Salt concentration affected acid taste; acid affected salt taste. This study revealed the effects of the ratio of acid and salt used in rainbow trout marinade on ripening and the resulting changes in sensory properties.

Spore germination and lactic acid combined treatment: A new processing strategy for the shelf-life extension of instant wet noodles

Bacillus amyloliquefaciens (BAM) was identified as the predominant spoilage bacteria in instant wet noodles (IWNs). The utilization of industrial acid treatment as a long shelf-life strategy resulted in reduced consumer acceptance due to the acidic taste of the products. This study proposed a processing strategy that integrated spore germination (SG) and lactic acid (LA) treatment to effectively reduce the spore survival rate and extend the shelf life of IWNs. L-histidine, d-glucose, and sodium chloride were highly efficient and safe germinants for BAM spores. In IWNs, compound germinants (1.0 % L-histidine, 0.5 % d-glucose, and 1.0 % sodium chloride) boosted the SG rate by 3.61 times. With synergistic LA treatment, the spore lethality increased by 34.41 % -41.68 %. Under the SG and reduced acid-heat conditions of pH 2.30–2.50, the mortality of spores could reach 92.00 %–93.17 %, which was 14.11 %–15.28 % higher than the industrial acid-heat condition of pH 2.10. DPA, ATP, and membrane potential showed that germinants reduced the spore membrane permeability and promoted the occurrence of spore membrane damage under acid-heat conditions. Moreover, this strategy significantly extended the shelf-life of IWNs by 3.00–5.50 times and controlled the pH ≥ 5.50. Additionally, it improved color, texture, and overall sensory evaluation. Accordingly, this strategy solved the contradiction between the long shelf-life of IWNs and the unacceptable acidification in industrial production.

Optimization of process parameters of refractance window drying for aonla slices and comparison with other drying techniques.

Aonla is as a good source of antioxidants due to its high ascorbic acid and polyphenol contents. However, because of its high acidity and astringent taste, aonla is rarely consumed in its fresh form. As the constituents in aonla are heat sensitive, it is essential to find a suitable drying method for preservation. Therefore, refractance window drying (RWD) of aonla slices was studied as it has the potential of retaining heat-sensitive compounds. The effect of RWD process variables, namely water temperature (75, 82.5, 90 °C) and slice thickness (2, 4, 6 mm), on different quality parameters of dehydrated aonla was studied. Increasing water temperature resulted in significantly higher ascorbic acid content, titratable acidity and product temperature, while total phenolic content, free radical scavenging activity and moisture content decreased. With the exception of product temperature, higher slice thickness led to an increase in the values of all the parameters. At the optimized processing conditions of 83 °C water temperature and 4 mm slice thickness, the ascorbic acid content, total phenolic content, free radical scavenging activity, titratable acidity and moisture content values were found to be 269.03 mg (100 g)-1, 242.33 mg (100 g)-1, 87.11%, 3.62% and 4% respectively. The aonla slices subjected to RWD also possessed 4-6% higher phytochemical content than osmotically dried and hot-air-dried samples. This research highlights the effectiveness of RWD in preserving heat-sensitive compounds in food like aonla. The RW-dried slices had a smoother and more uniform microstructure compared to osmotically dried and hot-air-dried samples. © 2024 Society of Chemical Industry.

Volatile Profile Characterization of Jujube Fruit via HS-SPME-GC/MS and Sensory Evaluation.

Current research does not fully elucidate the key compounds and their mechanisms that define the aroma profile of fresh jujube fruits. Therefore, this study conducted a comprehensive analysis of both free and glycosidically bound aroma compounds in fresh jujube fruits of ten cultivars. Utilizing gas chromatography-mass spectrometry (GC-MS), we identified 76 volatile free aroma compounds and 19 glycosidically bound volatile compounds, with esters, aldehydes, and ketones emerging as the predominant volatile compounds in the jujube fruits. Odor activity value (OAV) analysis revealed that the primary aroma profile of the jujubes is characterized by fruity and fatty odors, with β-damascenone being a key contributor to the fruity aroma, and (E)-2-oct-en-1-al and nonanal significantly influencing the fatty aroma. Moreover, the integration of sensory evaluation and partial least squares regression (PLSR) analysis pinpointed octanal, (E)-2-oct-en-1-al, nonanal, β-damascenone, and pentanal as significant contributors to the jujube's characteristic aroma, while isoamyl acetate was identified as significantly influencing the fatty acid taste. This study not only underscores the complexity of the jujube aroma composition but also highlights the impact of environmental factors on aroma profiles, offering valuable insights into the sensory characteristics of jujube fruits.

Karakteristik Sensori Produk Kopi 2 In 1 Komersial Menggunakan Metode Check-All-That-Apply (CATA)

The coffee industry in sachets is booming. Understanding the characteristics of product and what consumers want is the key to the success of the product developed. The purpose of this study was to obtain sensory profile information on commercial coffee 2 in 1 product using the CATA (Check-All-That-Apply) method. The testing method is divided into two, namely determining the sensory attributes of coffee by trained panelists through FGD (Focus Group Discussion) and CATA testing by consumer panelists including determining ideal attributes, coffee sample attributes and level of liking. The sensory attributes of coffee 2 in 1 based on FGD results for CATA testing are sweet aroma, acid aroma, roasted aroma, coffee aroma, caramel aroma, sweet taste, acid taste, bitter taste, caramel taste, coffee taste, watery body, thickness body, brown color, sandy texture, aftertaste bitter, aftertaste acid, and aftertaste sweet. The ideal coffee 2 in 1 product according to panelists should have a brown color, coffee aroma, coffee taste, roasted aroma, and sweet taste attributes. Attributes that affect consumer preferences are sweet taste, watery body, aftertaste sweet, coffee aroma, and brown color. The attributes of acid taste, acid aroma, and aftertaste acid are attributes that must not have and need to be considered for their existence. Product 235 has the highest level of favorability, which is 78%, while product 539 has the smallest percentage of 33%. Coffee 2 in 1 with ideal attributes according to consumers can still be developed further.

Characteristics of Hyloceregurt: Fermented Milk from Stems and Peel of Dragon Fruits

Background: Fruitghurt, the result of fruit or fruit by-product fermentation, is a functional food. Functional foods are foods that are rich in benefits. A formulation of hyloceregurt has been derived from the stem and peel of the dragon fruit (Hylocereus polyrhizus), with potential as an immunomodulatory agent. Objectives: This study is aimed at determining the quality of hyloceregurt. Material and Methods: Hyloceregurt formula variations are made from fermented stem powder, fruit peel powder, or dragon fruit peel juice. The test include physical characteristics, chemical analysis, microbiology analysis, and hedonic test. Results: Hyloceregurt formula from the stems of the plant and the peel of the dragon fruit has almost the same physical characteristics that include a distinctive smell, an acidic taste with a pH ranging from 3-5, and a thick liquid consistency. The color of the hyloceregurt follows the waste of the dragon fruit used (pink and green). The chemical characteristics of hyloceregurt have met the SNI standard, including fat content with a range of 3.1-3.6% and protein content with a range of 4.95–6.74% b/b. The microbiological characteristics of hyloceregurt indicate that the value of the total plate figure is in the range of 1.1-3.3 x 109 CFU/mL. Panelists on the hedonic test preferred three formulas: 1% hyloceregurt from the peel powder or fresh peel fruit juice, and dragon fruit plant stems based on smell, taste, color, and consistency. Conclusions: All formulas in 1% fruit or by-fruit were the most preferred formulas, and based on the best physical characteristic tests and chemical content analysis, met the requirements of SNI 2981 of 2009. However, microbiologically, they still did not meet the requirements of SNI 2981 of 2009, so further tests still need to be carried out.

Characterization of Amino Acid Composition, Nutritional Value, and Taste of Fruits from Different Actinidia arguta Resources

The nutritional value and flavor and texture characteristics of fruits from different Actinidia argute resources were scientifically evaluated and compared. Using 35 A. arguta fruits as materials, the amino acid composition and content were determined by an automatic amino acid analyzer, and differentiation analysis, amino acid nutritional value evaluation, TAV flavor analysis, correlation analysis, PCA comprehensive evaluation, and cluster analysis were conducted to clarify the diversity of A. arguta resources in terms of amino acid content, composition, and flavor characteristics. Analysis of differential results showed that the A. arguta resource fruits contained 17 amino acids with a total amino acid content of 384.20∼2590.56 mg/100 g. The results of the nutritional value evaluation showed that the Leu of the fruits of the A. arguta resources all conformed to the ideal model proposed by FAO/WHO, and the Leu content of all the resources exceeded the human body’s needs, and it was also found that the first limiting amino acid of the Actinidia argute resources was Ile and the second limiting amino acid was Lys. TAV of the flavor-presenting amino acids was calculated to evaluate the flavor-presenting taste characteristics, and the amino acids that influenced the flavor of A. arguta fruit were Glu and Cys. PCA showed that the 2 principal components could better reflect the comprehensive information of amino acids in A. arguta, and the cumulative variance contribution rate was 87.88%, which could represent the main trend of amino acids in A. arguta. A comprehensive amino acid evaluation model was established, and the composite scores indicated that the top 5 excellent resources were S4, S10, S18, S25, and S30. Hierarchical cluster analysis classified the 35 A. arguta resources into 4 categories, which better reflected the differences in amino acid content and composition, nutritional value, and taste characteristics among A. arguta fruits from different collection sites.

Karakteristik nutrisi dalam yoghurt pada susu sapi, kambing dan oat

Background: Yogurt is a dairy product produced by fermenting milk using starter cultures such as Lactobacillus bulgaricus and Streptococcus thermophilus bacteria. The use of these bacteria is due to their role in producing lactic acid. With the involvement of these bacteria, the liquid milk coagulates and develops a distinctive acidic taste. Methods: The research method employed in this article is qualitative research using a literature review approach. Finding: Based on the study results, it was found that cow's milk undergoes an increase in protein and carbohydrate levels after being transformed into yogurt. Goat's milk experiences an increase in carbohydrate and calcium levels post-yogurt production. Meanwhile, oat milk shows an increase in ash concentration and protein levels. Conclusion: The comparative results indicate that each yogurt from different sources offers distinct nutritional advantages. Therefore, it is important to consider the body's nutritional needs before consumption.

Developing a prediction method for physicochemical characteristics of Pontianak Siam orange (Citrus suhuiensis cv. Pontianak) based on combined reflectance-Fluorescence spectroscopy and artificial neural network

The slightly sweet and acidic taste offered by Pontianak Siam oranges is influenced by the total soluble solids (TSS) and acidity in the fruit, in which, measuring these attributes is commonly performed using instruments that potentially damage the fruit's structure, thus, impractical for fresh fruit products. Moreover, the process of classifying the quality of fresh oranges has been based on physical appearance, leading to subjective results. Correspondingly, the objective of the study is to develop a prediction method for the physicochemical characteristics of Pontianak Siam oranges based on VIS-NIR-Fluorescence spectroscopy and an artificial neural network (ANN) model. The method is applicable to classify oranges based on physicochemical characteristics without damaging the fruit's structure. As a result, the best model for classifying the maturity level of Pontianak Siam oranges was obtained using a dataset with all feature combined spectra, attaining a training accuracy of 0.99 and testing accuracy of 1. The best model for predicting TSS was obtained using all feature combined spectra dataset, attaining R2 training = 0.89 and R2 testing = 0.91. The best model for predicting acidity was obtained using all feature reflectance spectra datasets, attaining R2training = 0.96 and R2testing = 0.97. The best model for predicting fruit firmness was obtained using all feature reflectance spectra dataset, attaining R2training = 0.97, R2testing = 0.89. Overall, the combination of Vis-NIR reflectance and fluorescence spectroscopy have the potential to be applied for non-destructive assessment of citrus quality in terms of visual classification and maturity parameters prediction.

Phenotypic, Technological, Safety, and Genomic Profiles of Gamma-Aminobutyric Acid-Producing Lactococcus lactis and Streptococcus thermophilus Strains Isolated from Cow's Milk.

Gamma-aminobutyric acid (GABA)-producing lactic acid bacteria (LAB) can be used as starters in the development of GABA-enriched functional fermented foods. In this work, four GABA-producing strains each of Lactococcus lactis and Streptococcus thermophilus species were isolated from cow's milk, and their phenotypic, technological, and safety profiles determined. Genome analysis provided genetic support for the majority of the analyzed traits, namely, GABA production, growth in milk, and the absence of genes of concern. The operon harboring the glutamate decarboxylase gene (gadB) was chromosomally encoded in all strains and showed the same gene content and gene order as those reported, respectively, for L. lactis and S. thermophilus. In the latter species, the operon was flanked (as in most strains of this species) by complete or truncated copies of insertion sequences (IS), suggesting recent acquisition through horizontal gene transfer. The genomes of three L. lactis and two S. thermophilus strains showed a gene encoding a caseinolytic proteinase (PrtP in L. lactis and PrtS in S. thermophilus). Of these, all but one grew in milk, forming a coagulum of good appearance and an appealing acidic flavor and taste. They also produced GABA in milk supplemented with monosodium glutamate. Two L. lactis strains were identified as belonging to the biovar. diacetylactis, utilized citrate from milk, and produced significant amounts of acetoin. None of the strains showed any noticeable antibiotic resistance, nor did their genomes harbor transferable antibiotic resistance genes or genes involved in toxicity, virulence, or pathogenicity. Altogether these results suggest that all eight strains may be considered candidates for use as starters or components of mixed LAB cultures for the manufacture of GABA-enriched fermented dairy products.