Total Acid Value Research Articles

Quality Assessment of Deep-Frying Palm Oil by Impedimetric Sensing with a Simple and Economic Electrochemical Cell.

Quality control of deep-frying oil is a global public health concern. A simple and economic electrochemical chamber composed of two bare screen-printed carbon electrodes (working area: 78.54 × 102 cm2; distance: 0.0055 cm; cell constant: 0.70 × 10−2 cm−1) was constructed for precisely acquiring the impedimetric responses of a high-resistance palm oil sample (RSD < 7%, n = 3). Good correlations between the measured impedance data (charge transfer resistance and logarithmic output impedance (Log Z) obtained in the frequency region <0.1 Hz) and the regulatory quality indicators (total polar compounds and acid value) were achieved (R2 > 0.97), suggesting that the proposed impedimetric sensing method is useful for accurately assessing the deteriorated condition of repeated frying oil. Applications for rapid screening can also be realized because the measurement times of Log Z at any given perturbation frequency from 0.01–1 Hz were all less than 3 min.

Investigation of the effects of pomegranate juice addition on physicochemical, microbiological, and functional properties of set and stirred yogurts.

Pomegranate juice (PJ) (at concentrations of 13% and 17%) was added to yogurt and its physicochemical and microbial properties were investigated. PJ improved several features of yogurt, bringing an increase in total phenolic contents by 4.3–6.1 and 5.3–7.3 fold in response to 13% and 17% PJ, respectively. Also, there were increases in the total anthocyanin contents of yogurt by 2650–2870 and 3470–3820 fold in response to the said juice concentrations. These increases were observed in both set and stirred yogurts, whereas IC50 values of the yogurts decreased by 2.2–2.6 and 3.0–3.3 fold, respectively, compared to the control samples. Total acidity, syneresis, and redness value of the yogurts increased, parallel to the increase in the PJ concentration being added. Also, Streptococcus thermophilus count decreased significantly, whereas no significant effect was observed on the population count of Lactobacillus delbrueckii subsp. bulgaricus. Among PJ yogurt samples, the panelists selected the 13% PJ stirred yogurt as the best sample. PJ was observed to contain valuable bioactive compounds with functional and medicinal effects that culminate in health benefits.

Phyllanthus reticulatus Prevents Ethanol-Induced Gastric Ulcer via Downregulation of IL-8 and TNF-α Levels.

The current study aimed to determine the protective effect of P. reticulatus on ethanol-induced gastric ulcer. For this purpose, thirty-six Sprague-Dawley rats were divided into six groups. The first group served as normal control, while, in other five groups, absolute ethanol was used to induce gastric ulcer. Group II served as a diseased group, while groups III, IV, and V were treated with methanol extract, ethyl acetate fraction, and n-hexane fraction, respectively, in a dose of 400 mg/kg bodyweight. Group VI was given omeprazole in a dose 20 mg/kg bodyweight. The stomachs were removed, ulcer score was evaluated, and histopathological examination of gastric lumen was conducted. Total acidity and pH values were determined in gastric juice. TNF-α and IL-8 mRNA expressions levels were determined using the reverse transcription real-time PCR method. The data indicated that P. reticulatus protected against gastric ulcer, which was evident by attenuation of ulcer score. The pretreatment with P. reticulatus raised the gastric pH and improved all evaluated histopathological parameters such as ulcer score, erosion score, hemorrhage score, fibrinoid necrosis score, inflammatory infiltrate score, and edema score. P. reticulatus significantly reduced mRNA expression levels of TNF-α and IL-8. In conclusion, P. reticulatus possess antiulcer property which might be attributed to downregulation of TNF-α and IL-8 expression levels.

Performance of Ni-Mo Sulfated Nanozirconia Catalyst for Conversion of Waste Cooking Oil into Biofuel via Hydrocracking Process

The synthesis of the Ni-Mo sulfated zirconia (NiMo-SZ) catalyst and its application to convert waste cooking oil into biofuel was successfully conducted. The synthesis process was started with a sulfation process on the zirconia oxide (ZrO2) using 0.5, 1.0, and 1.5 M sulfuric acid (H2SO4) through wet impregnation to obtain sulfated zirconia (SZ). Solid SZ with the highest total acidity value was calcined at temperature 500, 550, 600, 650, and 700 °C. Solid SZ calcined with the optimum temperature was treated with Ni and Mo metals at 1%, 2%, and 3% (w/w) through a hydrothermal method. Pure ZrO2, SZ, and 1, 2, and 3 NiMo-SZ catalysts were used in the hydrocracking of used cooking oil into biofuel. The results showed that the 1.5 M SZ catalyst calcined at 500 °C had the highest acidity value of 3.8137 mmol/g. The 3-NiMo-SZ catalyst had the best activity valuing at 80.54%, while 1-NiMo-SZ produced the best selectivity in producing gasoline fraction until 73.93%.

Investigation of the pectin grafting with gallic acid and propyl gallate and their antioxidant activities, antibacterial activities and fresh keeping performance

In this paper, a method for the enzymatic modification of pectin, in which gallic acid (GA) and propyl gallate (PG) were grafted onto pectin molecules in an aqueous/organic two-phase system catalyzed by lipase, was proposed. The potential reaction mechanism was explored through UV–Vis, FTIR and 1H NMR spectroscopic methods and density functional theory. Results suggested that the lipase played a dual role during the modification by catalyzing the hydrolysis of methyl ester bonds of pectin in the aqueous phase and the esterification between the 4-OH of GA and PG and the –COOH of pectin in the organic phase. Moreover, the effects of GA and PG on the antioxidant and the antibacterial activities of pectin were evaluated, and results showed that the antioxidant and the antibacterial activities of modified pectin were better than those of native pectin. The effect of modified pectin on the quality of fresh bass (Lateolabrax maculatus) was further studied. Results suggested that, compared to control group, the total viable count, histamine level, malondialdehyde content and acid value of bass fillets treated with modified pectin were significantly reduced, whereas the sensory score was significantly increased.

The effects of different drying methods on some physical and chemical properties of ‘Eksikara’ grape cultivar grown in Karaman region

In this work, four different drying methods, namely natural drying in sun, natural drying in shade, natural drying in sun using a dipping solution and natural drying in shade using dipping solution were used to drying Ekşikara grapes growing in Karaman, Turkey. While aw values of all grapes were decreased during drying, total soluble solids content increased. The values of pH and total acidity in grape samples significantly increased during the drying period due to the increase in dry matter content. The results showed that all the drying treatments significantly increased the total phenolic content, total antioxidant activity, trans-resveratrol, organic acid and sugar compounds. Trans-resveratrol amounts were slightly higher in the samples dried in the shade and in the dipping solution treatment and decreased as the drying time increases. An increase in organic acid and sugar contents was observed depending on the drying time. The change of colour was comparatively faster in dried samples with dipping solution. It was found that dipping solution treatment (7 days) reduced the drying time by half when compared to the samples without dipping solution treatment (15 days). This result is important for the grape producers of Karaman/Turkey, where the drying period under sun generally take 15 days.

The Application of Nitrogen Fertilization and Foliar Spraying with Calcium and Boron Affects Growth Aspects, Chemical Composition, Productivity and Fruit Quality of Strawberry Plants

Strawberries are rich in antioxidants and plant components to enhance cardiac health and regulate blood sugar. This experiment investigates the effects of N fertilization and foliar spraying with calcium (Ca) and boron (B) on growth, chemical composition of plant foliage, fruit yield, and quality of strawberry plants (Fragaria × ananassa Duch. cv. Fortuna). This experiment includes 12 treatments from the combination between four N fertilizers treatments (combinations of mineral and organic fertilizers) and three foliar spraying treatments with Ca+B at 2 and 4 mL/L in addition to the control treatment (spraying with tap water). Results show that the treatment where 50% of the recommended dose of N (50% RDN) was applied with mineral fertilizer + 100% organic N was the most effective one since it induced the highest values of plant height, number of crowns per plant, number of leaves per plant, fresh and dry weight per plant, especially when combined with the foliar application of Ca+B at the highest tested rate (4 mL/L). The highest values of N, P, K, Ca, B, and total carbohydrate contents were also scored for the combination of 50% RDN + 100% organic N and the foliar spraying with Ca+B at 4 mL/L in both growing seasons. In addition, the highest values of fruit yield per plant and per hectare, exportable fruit yield/ha, fruit firmness, fruit TSS, Vitamin C, total sugars, and anthocyanin, as well as the lowest values of total acidity were recorded for the combined treatment of 50% RDN + 100% organic and Ca+B at the highest rate (4 mL/L). The highest recorded value of length, diameter, and weight of fruit were scored by fertilizing strawberry plants with the recommended dose of mineral N (100% RDN) and spraying with Ca+B at the highest rate in both growing seasons. In conclusion, it could be suggested that fertilization of strawberry plants with half the recommended dose with mineral N fertilizer + 100% organic fertilizer and foliar spraying with Ca+B at 4 mL/L increases plant growth and improve yield parameters and fruit quality of the strawberry plants.

Adverse pregnancy outcomes and mother-to-child transmission in patients with hepatitis B virus infection and intrahepatic cholestasis of pregnancy.

The aim of this study was to investigate adverse pregnancy outcomes (APOs) and mother-to-child transmission (MTCT) of intrahepatic cholestasis in pregnancy (ICP) in hepatitis B virus infection (HBV) patients. We performed a retrospective study at Beijing Youan Hospital in China from January 2010 through May 2017. A total of 232 patients were enrolled, including 106 HBV-infected ICP patients (Group H + C), 20 ICP patients (Group C) and 106 HBV-infected patients (Group H). Characteristics, APOs and MTCT rate of HBV were compared between groups. Group H + C was subdivided into 3 groups according to total bile acid (TBA) values and gestational age at diagnosis (GA). APOs were also compared within Group H + C according to TBA values and GA. There was no difference in live birth delivery mode and APOs between Groups H + C and C. Compared with Groups H, no difference was in live birth and MTCT rates of HBV. However, cesarean section delivery and APOs rates were higher in Group H+C (p < 0.05). Compared with Group H, adverse maternal outcomes such as postpartum hemorrhage and premature birth were more likely to occur in Group H + C (p < 0.001). Adverse fetal outcomes, the proportions of amniotic fluid reaching III degrees (AFIII), NICU admission, neonatal asphyxia and SGA were significantly higher among Group H + C than Group H (p < 0.05). Contamination of the AFIII rate increased with increasing TBA (p < 0.05). The rate of preterm birth and small for gestational age (SGA) was more common in GA 28-32 w compared with GA < 28 w and > 33 w (p < 0.01). H + C patients had more APOs than HBV patients, but the difference was not significant when compared with ICP patients. Although we did not find any difference in MTCT rate between H + C and HBV patients, active treatment to prevent neonatal asphyxia and HBV infection should be considered. Therefore, it is necessary to emphasize maternal and fetal monitoring during pregnancy and delivery.

Quality changes in fresh noodles prepared by different heat treatments during storage

The effects of single heat treatment (98°C-4 min, before and after packaging) and double heat treatment (98°C-4 min +90°C-15 min) on the quality of fresh noodles during storage (25°C and 4°C) were investigated. The safe storage period was determined based on the microbial content. Heat treatment significantly reduced the bacterial content, water activity, polyphenol oxidase activity, total polyphenols content, acidity, and fat acidity value of fresh noodles during storage, and improved the texture and cooking properties of fresh noodles, especially the double heat treatment. Additionally, double heat treatment combined with low-temperature storage could effectively prolong the noodle shelf-life. Practical applications Fresh noodles are prone to spoilage and enzymatic browning during storage. Heat treatment, as one of the popular physical preservation technologies, can solve these problems effectively. At present, heat treatment technology is mainly used in the processing of fresh pasta, and its application in fresh noodles especially the influence of heat treatment on the quality of fresh noodles during storage has not been reported. In order to improve the quality and shelf life of fresh noodles, different heat treatments combined with packaging technology and low-temperature storage were investigated in this study. This study could provide useful information for applying heat treatment on extending the shelf life of fresh noodles.

Characterization and metal loading capacity of humic acids derived from composted rice straw and olive pomace affected by the humification degree

&lt;p&gt;Laboratory study was performed to assess the impact of humification degree of humic acids isolated from composted rice straw (RS) and olive pomace (OP) on the metal loading capacity of extracted humic acids with Fe, Mn and Zn at different pH values (4, 5 and 6). The results revealed that the highest values of total acidity, carboxyl and phenolic-OH groups were achieved by HA-c extracted from compost C. Both HA-c and FA-c realized more pronounced values of total carbon and nitrogen content. Adversely, HA-c and FA-c achieved less pronounced values of oxygen and hydrogen as well as H/C, O/C and C/N atomic ratios. The loading capacity of Fe&lt;sup&gt;+2&lt;/sup&gt; reached to optimum values at pH 5 for all studied humic acids. While the maximum loading capacity of Mn&lt;sup&gt;+2&lt;/sup&gt; or Zn&lt;sup&gt;+2&lt;/sup&gt; was achieved at pH 6. In this respect, the maximum loading capacity of Fe&lt;sup&gt;+2&lt;/sup&gt;, Mn&lt;sup&gt;+2&lt;/sup&gt; and Zn&lt;sup&gt;+2 &lt;/sup&gt;were obtained for HA-c followed by HA-d.&lt;/p&gt;

Non-Porous Sulfonic Acid Catalysts Derived from Vacuum Residue Asphaltenes for Glycerol Valorization via Ketalization with Acetone

In this study, an approach for the preparation of heterogeneous acid catalysts based on asphaltenes isolated from vacuum residue is proposed. Varying the conditions for the sulfonation of asphaltenes made it possible to obtain materials with an acid value of 1.16 to 2.76 meq g−1 and a total sulfur content of 6.4 to 12.3 wt%. The samples obtained were characterized by acid-base titration, nitrogen adsorption, sulfur elemental analysis and transmission electron microscopy techniques, and were studied as potential acid catalysts in the ketalization reaction between glycerol and acetone. Sulfonated asphaltenes (SA) were characterized by a homogeneous distribution of sulfonic groups over the granule surface and an almost complete absence of a porous structure. The ketalization reaction in the presence of SA proceeded without intradiffusion restrictions; as a result of which, their activity was higher than for known heterogeneous catalysts. The most active SA sample (total acid value, 1.16 meq g−1) had an apparent activation energy of 18.0 kJ mol−1, which was lower than the value obtained for the zeolite BEA-40 (29–53 kJ mol−1) and the Amberlyst 36 resin (27 kJ mol−1), and was close to the value for the homogeneous p-TSA catalyst (14.5 kJ mol−1). The SA heterogeneous catalysts did not show any acid leaching and had no loss of activity after five catalytic cycles, with the total turnover number TON = 7247.

PENGARUH PENAMBAHAN SARI WORTEL PADA YOGHURT DITINJAU DARI AW, KADAR AIR, VISKOSITAS, TOTAL ASAM TERTITRASI DAN KADAR PROTEIN

Yogurt is a form of beverage product from milk processing that utilizes microbes (Streptococcus thermophillus and Lactobacillus bulgaricus.). In the fermentation process of fresh milk into a semi-solid emulsion product, yogurt also has high nutritional content, one of which is protein. and low in fat. The purpose of this study was to determine the optimal percentage of addition of carrot juice to improve the quality of yogurt in terms of water activity (AW), viscosity, total titrated acid and water content. The ingredients used are cow's milk, carrot juice and plain yogurt starter. Iodine, 75% alcohol and distilled water. The method used in this research is experimental method Comletely Block Design of 5 treatments, namely the addition of carrot juice to yogurt with a concentration of 0%, 10%, 15%, 20%, and 25%. volume of milk (1 liter), with each treatment repeated 4 times. Data analysis used ANOVA (Analysis of Variance), followed by Duncan's Multiple Range Test. The results showed that the addition of carrot juice to yogurt could increase the value of Aw: P0 (0.9) to P4 (0.96), water content: P0 (88.96%) to P4 (92.58%), the total acid value. titration: P0 (0.57%) to P4 (0.67%) and protein content value: P0 (2.97%) to P4 (4.89%), the viscosity value decreased from P0 (216.75) cP) becomes P4 (148.00 cP). Based on the research analysis, it can be concluded that the use of carrot juice with a concentration of 15% gives the best results for yogurt with a value of Aw (0.94), water content (91.21%), viscosity (177.75 cP), total acid titrated (0 , 65%), and protein content (4.26%).

Optimization of the process of compound feed pelleting for fur animals

Currently, fur farming products are becoming more and more in demand. With the increase in the number of fur-bearing animals, it is necessary to produce compound feeds that provide high quality furs with minimal feed costs. Compound feed recipes with a fat content of 20% and higher were developed for fur animals. Feeding fodder in the form of granules produced by the technology, one of the stages of which is the process of granulating compound fodders with a high fat content with reasonable operating parameters of the granulator press, is expedient. Process studies using the method of statistical planning of a multivariate experiment were carried out to determine the optimal granulation parameters. The following factors influencing the process under consideration were chosen: the amount of added fat, the steam consumption, the gap between the roll and the press die. Specific energy consumption and crumbling served as criteria for assessing the influence of the selected parameters, which make it possible to assess adequately the efficiency of the process. The data obtained showed that the process of pelleting compound feed at optimal parameters makes it possible to obtain pellets, the quality of which meets the requirements of the standard. All the data obtained were within the calculated confidence intervals of the optimization parameters. The change in the quality indicators of the obtained granulated compound feed during storage was also investigated in the work. Changes in the quality of granulated compound feed during storage testified that the values of total acidity and acid number of fat increased significantly after two months of storage due to hydrolysis of fat in conditions of free oxygen access. The value of the peroxide number of fat, which reflects the depth of oxidative changes in the compound feed, increased sharply after two months of storage. The content of vitamins A and E during the storage of compound feed for 45 days in summer was 12.3% and 10.5% of the initial values, respectively. The recommended shelf life of granulated feed with a high fat content in winter-spring period is 60 days, in summer - 45 days.

Molecular Design and Dynamic Simulations of Some Novel Antioxidant Lubricant Additives

A quantitative structure-property relationship (QSPR) in-silico study was performed to develop a mathematical model that correlates 2D and 3D descriptors of 37 antioxidant lubricant additives (compounds) with their properties. A molecular dynamics simulation study was also carried out to access these additives' binding strength on diamond-like carbon (DLC) and steel crystal surfaces. Five novel antioxidant lubricant additives were designed from the information derived from the QSPR mathematical model’s high coefficient molecular descriptors. All the novel lubricant additive’s antioxidant properties were found to be better than our previous study, with the lubricant additive (Z)-3-(4-(5-amino-1-phenyl-1H-pyrazol-3-yl)-3,5-dimethylphenyl)-2-phenyl-5-(thiophen-2-ylmethylene)-3,5-dihydro-4H-imidazol-4-one found to possessed excellent antioxidant properties of 0.850281 total acid values (T.A.V 0.1g/L) than its co-additives. Moreover, all the designed additives dynamically bind to steel crystal surfaces excellently from our dynamic simulation study than the DLC crystal surface. The molecular dynamics simulation results were found to be better than the one reported by our previous study. This investigation will help synthesize novel and excellent antioxidant lubricant additives that will hinder the base oil from undergoing a complete oxidation cycle and meet environmental requirements as these novel additives do not contain Zinc and Phosphorus, which often rendered exhaust pipes catalytic converter inactive, thereby increasing environmental pollution.

Fermentation and Extrusion effects on Nutritional and Organoleptic Compositions of Unripe Plantain and Pigeon Pea Blends

This research investigated effects of fermentation and extrusion on unripe plantain and pigeon pea blends. The samples were blended and prepared in three combinations (A=100g unripe plantain; B= 70g unripe plantain: 30g pigeon pea; C= 50g unripe plantain: 50g pigeon pea) and sectioned into four group (i.e. group 1 = preconditioned and fermented; group 2 = extruded; group three = fermented and extruded; and group 4 = unfermented/unextruded). Semi-solid state fermentation method was employed to ferment the blended samples for 96 hours. The physicochemical parameters (i.e pH, temperature and total titratable acidity) of these fermented samples were evaluated. The total microbial counts include; 9 bacteria, 2 yeasts and 4 molds were isolated and identified as; Bacillus subtilis, Bacillus cereus, Micrococcus luteus, Staphylococcus aureus, Lactobacillus plantarum, Lactobacillus fermentum, Leuconostoc mesenteroides, Lactobacillus mali, Streptococcus lactis, Saccharomyces cerevisiae, Candida utilis, Aspergillus niger, Aspergillus fumigatus, Aspergillus candidus, and Mucor hiemalis. There were significant variations in the values of pH and total titratable acidity (TTA) during fermentation. This was also same for the proximate contents of the fermented and extruded flour blends when contrasted with the raw flour blends. The fermented unextruded group 1 (11.73±0.01%) has the highest moisture contents and least in the raw sample B (6.34±0.00%). The raw flour blends protein content increased from 2.57±0.03 to 10.17±0.00% and from 2.58±0.02 to 16.27±0.01% in the fermented extruded blends. The carbohydrate content in the raw flour blends was highest (67.97±0.02 to 74.32±0.00%) and least in fermented unextruded samples (38.28±0.01 to 62.72±0.01%). The fat content was highest in the fermented unextruded blends (2.52±0.01 to 6.33±0.00%) and least in raw blends (1.33±0.02 to 2.01±0.02%). The sensory evaluation of the samples showed a good preference for fermented-extruded samples. Findings from this research have established that fermented and extruded unripe plantain and pigeon pea blend enhanced nutritional value of food.

ULTRASONİK VE ELEKTRİKSEL ÖN İŞLEMLERİN KİVİ DİLİMLERİNİN KURUMA VE KALİTE ÖZELLİKLERİNE ETKİSİ

In this study, the drying characteristics and quality properties of electrical (ET) and ultrasound (US) pre-treated kiwi fruit slices were investigated. Electrical and ultrasound pretreatments were carried out on the parameters of 100 V- 40 sec. and 35 kHz-30 min respectively. After the pretreatments, the kiwi fruit slices were dehydrated using a convective dryer at 50°C and 1.5 m/s air flow rate. The effects of these pretreatments on the drying rate and quality properties (the total phenolic content, vitamin C, pectin contents, rehydration rate, acidity, and color values) were evaluated. Consequently, the US and ET pretreatments provided an increase in the drying rate by 18.34% and 21.65% respectively. The combination of pretreatments (ET+US) increased the drying rate by 35.70%. The ET pretreatment produced minimum changes in the samples' pectin content and color values, and the US application increased the vitamin C, rehydration capacity, and acidity.

Fermentation and Exrusion Effects on the In Vitro Proteinand Starch Digestibility of Unripe Plantain and Pigeon Pea Blends

This study investigated effects of fermentation and extrusion on the in vitro protein andstarch digestibility of unripe plantain and pigeon pea blends. The blended samples were set-up in three arrangements (A=100g unripe plantain; B= 70g unripe plantain: 30g pigeon pea; C= 50g unripe plantain: 50g pigeon pea) and divided into four batches (i.e. first batch = preconditioned and fermented; second batch = extruded; third batch = fermented and extruded; and fourth batch = unfermented/unextruded). Semi-solid state method of fermentation was deployed to ferment blended samples for 96 hours. The pH, temperature and total titratable acidity (TTA) of these samples were evaluated. Fifteen microorganisms comprising 9 bacteria, 2 yeasts and 4 molds were isolated and identified as; Bacillus subtilis, Bacillus cereus, Micrococcus luteus, Staphylococcus aureus, Lactobacillus plantarum, Lactobacillus fermentum, Leuconostocmesenteroides, Lactobacillus mali, Streptococcus lactis, Saccharomyces cerevisiae, Candida utilis, Aspergillusniger, Aspergillusfumigatus, Aspergilluscandidus, and Mucorhiemalis. There were notable variation in the values of pH and total titratable acidity (TTA) during fermentation. The processes of fermentation and extrusion significantly amplified the in vitro starch digestibility of the flour blends with fermented extruded samples (51.03±0.02 to 55.19±0.02mg/ml) unlike theraw flour blends (36.77±0.20 to 41.26±0.003mg/ml).The in vitro protein digestibility significantly increased with the extruded fermented samples (12.73±0.17 to 15.45±0.06mg/ml) and lowest forraw flour blends (4.57±0.29 to 5.98±0.37mg/ml). Hence, it can be concluded based from the available information from this study that fermentation and extrusion increase the in vitro starch digestibility and protein digestibility of unripe plantain and pigeon pea blends.

Selection of potential probiotics with cholesterol-lowering properties for probiotic yoghurt production.

From 61 lactic acid bacteria (LAB) isolates, three had good cholesterol-lowering properties, with Limosilactobacillus fermentum KUB-D18 having the highest cholesterol assimilation (68.75%) (51 µg/109 CFU). In addition, Lactiplantibacillus pentosus HM04-25 and L. pentosus HM04-3 had the two highest levels of bile salt hydrolase (BSH) activity (22.60 and 21.45 U/mL, respectively). These three strains could resist four antibiotics (aztreonam, vancomycin, teicoplanin, and nalidixic). However, fortunately, they contained no mobile antibiotic resistance genes. To evaluate the influence of probiotic strains in yoghurt production, L. fermentum KUB-D18, L. pentosus HM04-25, or L. pentosus HM04-3 were simultaneously cultured with commercial yoghurt starter (YF-L812) and incubated at 43 °C for 6 h. During yoghurt fermentation, the total bacteria in the yoghurt tended to increase from 7.39 to 8.90 log CFU/mL. The growth rates of two probiotic strains (L. pentosus HM04-25 and L. pentosus HM04-3) were stable at 6.06 to 6.62 log CFU/mL. Only the rate for L. fermentum KUB-D18 increased (to 7.5 log CFU/mL). These three probiotics did not affect the physical characteristics of yoghurt. The total soluble solids, pH, and titratable acidity values of the probiotic yoghurts were similar to the control yoghurt at 30Brix, 4.91, and 0.90%, respectively. The firmness values of the probiotic yoghurts and the control were not significantly different (p > 0.05). Differentiation of the appearance of color, odor, flavor, and texture between the control yoghurt and the probiotic yoghurts was investigated using 56 volunteers and no significant differences were identified. Additionally, sensory evolution revealed that the acceptability of the probiotic yoghurts was higher than for the control (p ≤ 0.05). Therefore, the three probiotic strains with cholesterol-lowering properties had potential in future yoghurt production.

Comparative analysis of the effects of novel electric field frying and conventional frying on the quality of frying oil and oil absorption of fried shrimps

Production of high-quality fried foods with low oil content receives considerable attention from consumers and producers. The effects of electric field frying (EFF) and conventional frying (CF) on the physicochemical properties of frying oil, the oil absorption behavior, and the microstructural changes in fried shrimps were compared and evaluated in this study. Results showed the application of EFF could delay the degradation of frying oil evidently compared with CF. The increasing rate of total polar compound content, acid values, viscosity, and color deepening of EFF oil was slower (p < 0.05) than that of CF oil during the prolonged frying. The analysis of the results of low field nuclear magnetic resonance (LF-NMR) measurements confirmed our findings. In addition, the fried shrimps produced by EFF had reduced oil content (p < 0.05), increased water retention (p < 0.05), even oil distribution, and decreased microstructure damage via the observation of magnetic resonance imaging, confocal laser scanning microscope (CLSM), and scanning electron microscope. Results may provide ideas for producing high-quality fried products with low oil content and delaying oil degradation during frying.

Quantitative analysis of fish meal freshness using an electronic nose combined with chemometric methods

Total volatile basic nitrogen (TVB-N) and acid value (AV) are the main indicators for characterizing fish meal freshness. To explore the feasibility of fish meal freshness detection based on an electronic nose system, a portable electronic nose measurement system was developed to detect the TVB-N and AV mass fraction in fish meal. The device is mainly composed of a gas acquisition and transmission module, a control and processing storage module with Raspberry Pi as the core, an ARPI600 data acquisition module, and a sensor array module. The system was used to collect the odour signals of fish meal samples with different TVB-N and AV mass fractions and the chemical test was conducted for the TVB-N and AV mass fractions in fish meal samples. The feature selection method of recursive feature elimination based on random forest (RFRFE) was used to select the sensor array features, and models of the TVB-N and AV mass fraction in fish meal were established by random forest regression (RFR) and least squares support vector machine (LSSVM) model based on the particle swarm optimization (PSO) algorithm, and the models were verified by a test sample. The experimental results show that the performance of the LSSVM regression model based on the RFRFE optimized sensor array data set is better than that of the traditional LSSVM model, The R2 and root mean square error (RMSE) between the predicted values and the real values for AV and TVB-N based on the test set are 0.8585, 0.3622 and 0.8789, 20.52, respectively. Therefore, the performance of feature selection using the RFRFE method is better. The results show that the TVB-N and AV of fish meal can be detected effectively by electronic nose technology.