To optimize the spice-brine formulation and processing technology of Hainan selenium-enriched marinated eggs by single-factor and orthogonal experiments, and systematically analyse the influence of key factors on the sensory quality and textural properties of the marinated eggs.

The optimal formulation and processing conditions for the marinated eggs were determined using ranking tests in combination with a sensory scoring method. Textural profile analysis was performed with a texture analyzer to evaluate the textural parameters of the marinated eggs under different processing conditions.

The optimal spice-brine formulation for the marinated eggs was determined as follows: 1.50% of type I spices, 0.67% of type II spices, 4.00% granulated sugar, 1.60% salt and 5.50% light soy sauce. The marinated eggs prepared using this formulation exhibited a uniform brown color with a glossy surface. Sensory evaluation indicated a rich and harmonious aroma, moderate elasticity, and an appropriate level of saltiness and umami, demonstrating excellent overall sensory quality with the highest comprehensive score. The optimal processing conditions for the marinated eggs were established as follows:Marinating for 60 min, cooling naturally to room temperature, refrigerating at 4 ℃ for 12 h, followed by draining and drying at 60 ℃ for 60 min. Under these optimized conditions, the hardness and chewiness of the egg white were(1496.06±13.53) g and (1169.31±126.95) g, respectively, while the hardness and chewiness of the egg yolk were(317.11±2.34) g and (196.10±8.61) g, respectively. All textural parameters were significantly superior to those of non-marinated eggs (P<0.05).

This study effectively improves the sensory quality and texture properties of marinated eggs. It provides a standardized basis for the deep-processing industry of Hainan selenium-enriched eggs and offers key technical support for the large-scale and high-quality development of this industry.

To systematically evaluate the nutritional composition and quality characteristics of different commercially available brands of ready-to-cook grilled fish.

Ready-to-cook grilled fish samples from 8 different brands were collected, and variations in indicators including basic composition, amino acids, fatty acids, sensory evaluation, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARs), color, shear force and water-holding capacity were analyzed.

There were significant differences in the moisture, crude protein, crude fat and ash content among the 8 brands of grilled fish (P<0.05). The amino acid composition of roasted fish was consistent, with essential amino acids (EAA)/total amino acids (TAA) at 0.45, and EAA/non-essential amino acids (NEAA) ranging from 0.81 to 0.83. This met the standard for high-quality protein. The ready-to-cook grilled fish contained unsaturated fatty acids (UFA) accounting for 78% of the total fatty acids, content of oleic acid and linoleic acid was relatively high. Regarding quality characteristics, the comprehensive sensory scores of HY-1 to HY-4 were superior to those of HY-5 to HY-8. The TVB-N (5–8 mg/100 g) and TBARs (<2.2 mg/kg) of the 3-month stored samples were all well below the established limits, indicating good freshness and compliance with safety standards.Significant differences in color, shear force and water-holding capacity were observed among the ready-to-cook grilled fish products from different brands (P<0.05), which could be attributed to variations in raw materials and processing parameters. The results of low-field nuclear magnetic resonance indicated that there were significant differences in the content of immobilized water and free water among different brands. The grilled fish samples exhibited pronounced signals for nitrogen oxides, methyl compounds, sulfides, alcohols, aldehydes/ketones and organosulfur compounds, along with analogous principal component profiles.

The 8 brands of ready-to-cook grilled fish maintain well-preserved nutritional value, freshness and edible safety, while variations in raw materials and processing techniques among different brands give rise to significant product differences. This study aims to scientifically evaluate the overall quality of commercially available ready-to-cook grilled fish, clarify the current situation and challenges of ready-to-cook grilled fish, and provide a scientific basis for promoting the high-quality development of the ready-to-cook grilled fish industry.

To establish an analytical method for the simultaneous determination of 50 kinds of mycotoxins in Dimocarpus longan Lour. and its dried products by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Samples were ultrasonically extracted with formic acid-acetonitrile-water (1:79:20, V:V:V), and purified with an Oasis PRiME HLB solid-phase extraction column.Chromatographic separation was performed on a Waters CORTECS T3 column (2.1 mm×100 mm, 2.7 μm) with gradient elution using 0.1% formic acid aqueous solution and methanol-acetonitrile (4:6, V:V) as mobile phases.Detection was carried out in positive and negative electrospray ionization modes with multiple reaction monitoring, and quantification was achieved using the matrix-matched external standard method.

Under optimized conditions, the 50 kinds of mycotoxins exhibited good linearity in a certain mass concentration (r²>0.995). The limits of detection and limits of quantitation were 0.03–3.48 μg/kg and 0.10–11.59 μg/kg, respectively. The average recoveries at 3 spiked levels (low, medium and high) ranged from 76.3%–119.6%, with relative standard deviations of 0.45%–9.02%. The established method was applied to the analysis of 62 batches of Dimocarpus longan Lour. and its dried products and 16 kinds of mycotoxins were detected in 21 samples, with the average contents ranging from 0.42–13.51 μg/kg.

The established method is simple in operation, high in sensitivity and accurate in results, which is suitable for high-throughput screening and quantitative detection of 50 kinds of mycotoxins in Dimocarpus longan Lour. and its dried products.

To develop ice cream with Pisum sativum and Pyrus ussuriensis Ruan’er using Pyrus ussuriensis Ruan’er produced in Gaolan County, Lanzhou as the core raw material.

Suitable compound gums were screened through single-factor experiments. The effects of 6 kinds of edible gums—xanthan gum, carrageenan, guar gum, locust bean gum, gelatin and sodium carboxymethyl cellulose (CMC-Na) on the sensory quality and melting properties of the ice cream were compared to determine the optimal compound edible gum. Based on these results, an L₉(3³) orthogonal experiment was designed with the addition levels of compound gum (0.100%, 0.125%, 0.150%), milk powder (30%, 35%, 40%), and Pyrus ussuriensis Ruan’er juice (25%, 30%, 35%) as key factors. The formula was optimized by combining the fuzzy mathematics sensory evaluation method.

The optimal formulation for the Pisum sativum and Pyrus ussuriensis Ruan’er ice cream was determined as follows:Compound gum 0.125%, Pyrus ussuriensis Ruan’er juice 35% and milk powder 35%. Under this formulation, the product achieved a comprehensive sensory score of 91.2, exhibiting uniform color, a harmonious aroma of Pyrus ussuriensis Ruan’er and milk, and a delicate texture. The content of total solids, fat and protein was 31.2, 6.4 and 2.91 g/100 g, respectively. The ice cream demonstrated good melt-resistance and a relatively high protein content.

The Pisum sativum and Pyrus ussuriensis Ruan’er ice cream formula developed in this study is scientifically rational and exhibits distinct regional characteristics. All its core physicochemical indicators meet the requirements of GB/T 31114—2014 Frozen drinks-Ice cream, and the product has prominent nutritional advantages.This study provides both theoretical and practical references for the high-value development and utilization of Pyrus ussuriensis Ruan’er as well as for the innovative research and development of characteristic Chinese frozen foods.

To establish a method for the simultaneous determination of trace elements in Pyrus sinkiangensis Yu and Qiuli lung moistening paste by pressure tank digestion and inductively coupled plasma mass spectrometry (ICP-MS).

The samples were digested in a pressure tank at 80 ℃ for 2 h, 120 ℃ for 2 h and 165 ℃ for 4 h, and then analyzed by ICP-MS. The accuracy and reliability of the method were evaluated through methodological studies.

The linear relationship of each element was good within a certain range (r>0.9996)based on the results of the methodological studies. The relative standard deviations (RSDs) of precision were 0.03% to 8.32%, indicating good instrument precision. The RSDs of repeatability were 0.03% to 3.17%, indicating good repeatability. Both Pyrus sinkiangensis Yu and Qiuli lung moistening paste contained 16 kinds of trace elements including beryllium, boron, titanium, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, gallium, arsenic, strontium, cadmium, barium and lead. Pyrus sinkiangensis Yu contained more lithium than Qiuli lung moistening paste. The content of 8 kinds of elements including titanium, vanadium, chromium, manganese, cobalt, nickel, zinc and cadmium in Qiuli lung moistening paste made from Pyrus sinkiangensis Yu was higher than those in the main raw material.

This method requires a small sample size, has a low limit of detection, high sensitivity and accuracy, and can be used for the simultaneous determination of multiple Pyrus sinkiangensis Yu.

To establish a method for the simultaneous determination of dichloroacetic acid (DCAA)and nitrite in water by suppressed ion chromatography, and optimize their separation conditions through response surface methodology.

Thermo Scientific Dionex IonPac™ AS19 anion exchange column was used. Taking the separation degree of DCAA and nitrite as the core evaluation index, the effects of 3 key factors (column temperature, DCAA concentration and eluent concentration) on the separation degree were investigated by single-factor experiments. Building upon this, a Box-Behnken central composite design was employed to construct a response surface model, thoroughly exploring the interactions between the factors and determining the optimal separation conditions.

The optimal separation conditions obtained by response surface methodology were as follows: column temperature 25 ℃, DCAA mass concentration 1000 μg/L and eluent mass concentration 6 mmol/L (with nitrite mass concentration fixed at 100 μg/L as the experimental background). Under the optimized conditions, the separation degree between DCAA and nitrite reached 2.71, meeting the requirement for effective separation of components during detection. Methodological validation results demonstrated good linearity within a certain concentration range(determination coefficient r²>0.999), the relative standard deviations were below 3.5%, and spike recovery rates were 95%-107%. These findings indicated that the method possessed high accuracy and stability.

The detection method optimized in this study can effectively achieve simultaneous and accurate determination of DCAA and nitrite in water. It is characterized by simple operation, high efficiency and reliability, making it suitable for the routine monitoring of these 2 kinds of substances in actual drinking water. This provides strong technical support for water quality safety assessment.

To determine of γ-aminobutyric acid (GABA) in suancai fermentation broth by high performance liquid chromatography with diode array detection (HPLC-DAD) coupled with pre-column derivatization with dansyl chloride.

In this study, HPLC-DAD was used to perform real-time online spectral scanning of derivatives. Combined with single factor experimental method, the derivatization reaction conditions and chromatographic separation parameters were systematically optimized.

Using NaHCO₃-Na₂CO₃ as buffer system, 45 ℃ water bath derivatization reaction for 5 min, and without ammonia, the derivatization effect was the best, but the sample pH still needed to be adjusted to more than 10 when determining the suancai fermentation broth. The mobile phase with 0–15 min, 30%–42% acetonitrile, 70%–58% 20 mmol/L phosphoric acid could not only achieved a stable baseline, but also made the target and interferents baseline separation. when the organic mobile phase changed from methanol to acetonitrile, the derivative λ_max changed from 219 nm to 222 nm, that was the λ_max shifted red. At the wavelength of λ_max(222 nm), coefficient of determination reached 0.99999, with the highest sensitivity and the lowest limit of detection (0.023 mg/L), which revealed that λ_max was the optimal detection wavelength. The method validation results showed that the optimized method exhibited a good linear relationship within the mass concentration range of 0.05–100.00 mg/L. The limit of detection of the method was 0.074 μg/mL, and the limit of quantitation was 0.241 μg/mL. The recovery rate was 87.02%–107.25%, with a relative standard deviation of 2.34%–3.49%. Furthermore, it was found that GABA had poor stability and should not be stored for extended periods even under refrigeration.

The optimized method can be used to determine GABA in suancai fermentation broth with complex matrices, demonstrating good sensitivity, precision and reproducibility. It is also confirmed that ammonia can induce derivative side reactions, changes in the organic mobile phase can cause changes in λ_max, and the GABA has poor stability.

To determine the best medium composition and fermentation conditions to maximize the production of exopolysaccharides from Lentinula edodes through submerged fermentation, as well as to analyze the structure and assess the antioxidant properties of the extracted exopolysaccharides.

Single-factor experiments were conducted to identify the optimal carbon and nitrogen sources and their concentrations. Furthermore, 3 key factors influencing the yield of Lentinula edodes exopolysaccharides—pH, liquid volume and agitation speed were selected for response surface methodology optimization under controlled fermentation parameters (pH, liquid volume, rotation speed, inoculum size and fermentation time). The exopolysaccharides produced under these optimized conditions were characterized using scanning electron microscopy, ultraviolet spectroscopy, infrared spectroscopy and thermogravimetric analysis. Their ability to scavenge free radicals, including 1, 1-diphenyl-2-trinitrophenylhydrazine(DPPH), 2, 2-biazo-di (3-ethyl-benzothiazolin-6-sulfonic acid) diammonium salt, and hydroxyl radicals, was also evaluated.

Glucose at 20 g/L and yeast extract at 5 g/L were identified as the optimal carbon and nitrogen sources, respectively, for submerged fermentation of Lentinula edodes. The ideal fermentation parameters were pH 6, liquid volume of 101 mL, agitation speed of 149 r/min, inoculum size of 5% and an 8-day fermentation period. Scanning electron microscope images showed that the exopolysaccharides had a loose structural morphology. Ultraviolet spectroscopy revealed no absorption peaks indicative of nucleic acids or proteins, while infrared spectroscopy displayed characteristic polysaccharide absorption bands at 3408.1, 2920.5, 1646.1 and 1324.5 cm^–1. Thermogravimetric analysis demonstrated that the polysaccharides maintained good thermal stability between 28 ℃ and 180 ℃. The exopolysaccharides exhibited strong antioxidant activity, with scavenging rates of 60.14% for DPPH radicals, 53.47% for ABTS cationic radicals and 93.94% for hydroxyl radicals.

The study optimize the submerged fermentation process for producing exopolysaccharides from Lentinula edodes, confirming the method’s stability and practicality. These findings provide a theoretical foundation for enhancing fermentation efficiency, increasing polysaccharide yields and supporting further development and application of Lentinula edodes polysaccharides.