Band 16, Heft 8

Consumption of functional juice is becoming increasingly popular. This study aimed to evaluate the effect of probiotic fermentation with Bacillus sp. DU-106; Lactobacillus planturum Lp-43 and Lactobacillus rhamnosus Lr-156 on the biochemical and functional characteristics, antioxidant activities and storage stability of Dendrobium officinale and banana (DOB) juice. The cell levels of the lactic acid bacteria reached near 9 log copies/mL after fermentation at 32 °C for 36 h and could keep in this level after storage at 4 °C for 28 days. After fermentation, total acidity, flavonoids and polysaccharide contents of DOB juice increased, while pH, dissolved oxygen, nitrite, nitrate, vitamin C, β-carotene, sugar contents and antioxidant capacity slightly decreased. Compared with nonfermented DOB juice, polyphenol oxidase (PPO) and peroxidase (POD) activities of fermented DOB decreased significantly, but the color value and the content of total phenols and vitamin C decreased slightly in fermented DOB juice during storage. Overall, the probiotic fermentation with selected strains could improve the quality the DOB juice, enhance antioxidant capacity and storage stability, and destroy accumulation of nitrite and nitrate during storage. Findings of this study would help in the development of beneficial beverages in industrial production.

Effects of Weissella strains ( Weissella cibaria X31 or Weissella confusa L2) as starters on the physicochemical, volatile, proteolytic, microbiological, and sensory properties of low-nitrite dry-fermented sausages were evaluated for 20 d. Results showed that the addition of 8 log CFU/g of Weissella strains increased the redness, hardness, adhesiveness, and chewiness, but decreased the pH, water activity, and nitrite content of sausages during processing. Morover, Weissella strains inhibited the growth of Salmonella enterica . Weissella strains also could hydrolyze myofibrillar proteins in sausages. The sausage inoculated with W. confusa L2 was more abundant in ester compared with the control. Sausages inoculated with W. cibaria X31 and W. confusa L2 and sodium nitrite (0.05 g) had more desirable characteristics, compared with other groups. W. cibaria X31 and W. confusa L2 show potential as multifunctional starters in low-nitrite fermented sausage, which is uniqueness and addressed the gap of Weissella in low nitrite sausages. This study is distinct in that Weissella strains were found to improve the redness of dry-fermented sausages and was effective at partly replacing nitrite in dry-fermented sausages, addressing the research gap regarding the application of Weissella in low-nitrite sausages.

In this study, the moisture diffusion process and mass transfer resistances for the drying process of corn were studied numerically. A 3D mathematical model for the heat and mass transfer of the hot air drying of corn was established. The heterogeneity of the corn kernels' physical structure was designed by multi-component modeling of the corn geometry. The distributions of the temperature and moisture inside the kernel during the drying process were simulated by COMSOL Multi physics software. The effects of drying air temperature, relative humidity, and wind velocity on the mass transfer process of drying corn were analyzed. The pericarp resistance comprised the majority of the mass transfer resistance in the drying process. The drying air temperature significantly reduced pericarp resistance. The higher the wind velocity was, the lower the boundary layer resistance.

Rice bran oil extracted by the water-enzymatic method was placed at a temperature of −5 °C for 8 h. Light-phase rice bran oil with an iodine value of 112.13 ± 0.21 g I 2 /100 g oil was separated by cryogenic freezing centrifugation. Lipozyme RM IM transesterified light-phase rice bran oil and conjugated linoleic acid (CLA) under supercritical system CO 2 (SC-CO 2 ). The optimal reaction conditions for transesterification of CLA and rice bran oil in SC-CO 2 were determined as follows: the Lipozyme RM IM dosage was 9%, and the RBO/CLA molar ratio was 1:3, the reaction temperature was 55 °C, stirring speed was 300 rpm, and transesterification time was 20 h, the CLA conversion rate can reach 42.1%.

Tricholoma matsutakeis (TM) is the most expensive edible fungi in China. Given its price and exclusivity, some dishonest merchants will sell adulterated TM by combining it with cheaper fungi in an attempt to earn more profits. This fraudulent behavior has broken food laws and violated consumer trust. Therefore, there is an urgent need to develop a rapid, accurate, and nondestructive tool to discriminate TM from other edible fungi. In this work, a novel detection algorithm combined with near-infrared spectroscopy (NIR) and functional principal component analysis (FPCA) is proposed. Firstly, the raw NIR data were pretreated by locally weighted scatterplot smoothing (LOWESS) and multiplication scatter correction (MSC). Then, FPCA was used to extract valuable information from the preprocessed NIR data. Then, a classifier was designed by using the least-squares support-vector machine (LS-SVM) to distinguish categories of edible fungi. Furthermore, the one-versus-one (OVO) strategy was included and the binary LS-SVM was extended to a multi-class classifier. The 166 samples of four varieties of fungi were used to validate the proposed method. The results show that the proposed method has great capability in near infrared spectra classification, and the average accurate of FPCA-LSSVM is 97.3% which is greater than that of PCA-LSSVM (93.5%).

Ultrasonic evaporator is a new type of evaporation equipment using ultrasonic technology to assist evaporation and concentration. It is especially suitable for the materials which are easy to scale and foam. Due to the complexity of heat and mass transfer during ultrasonic technology to assist liquid evaporation process, there are few reports on the energy consumption of ultrasonic evaporation. In this paper, the effects of ultrasonic density, evaporation temperature, and feed flow rate on the total energy consumption of ultrasonic evaporation were studied and tap water was selected as experimental material. It was found that the optimal condition for this ultrasonic evaporator were the ultrasonic power density of 4 × 10 −5  W/m 2 , the evaporation temperature of 65 °C, and the feed rate of 1.389 × 10 −5  m 3 /s. According to the orthogonal test and analysis of variance, it can be obtained that the influence of evaporation temperature on total energy consumption is the largest, the second is feed flow rate, and ultrasonic power density has the least influence.

The present study was carried out to produce a high quality puffed infant rice cereal from rice and mung bean through extrusion technology. Experiments were designed using 3 independent variables (i. e. 14–18% feed moisture, 400–550 r/min screw speed and 125–175 °C barrel temperature) and 3 response variables (i. e. bulk density, water solubility index and degree of gelatinisation) at five different levels of central composite rotatable design (CCRD). The results of optimization demonstrated that 14% feed moisture, 400 r/min screw speed and 175 °C barrel temperature could generate rice-mungbean extrudates with desirable functional properties. The selected extrudate samples were further examined using scanning electron microscope (SEM), rapid viscosity analyzer (RVA), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD) analysis, in vitro digestibility and fundamental nutrient analysis. Notably, the initial oval-shaped particle structure of starch in the raw materials disappeared, the surface debris and roughness increased, and the density decreased. The time required for the gelatinization of puffed infant rice cereal was the shortest, which was in agreement with the positioning of ready-to-eat weaning food for infants. Moreover, the puffed infant rice cereal displayed higher peak viscosity and breakdown value, smaller retrogradation value and greater top taste value compared to the commercial infant rice cereal. Besides maintaining the initial characteristic peak of starch, the puffed infant rice cereal demonstrated characteristic absorption peaks of COO- in the vicinity of 1546 cm −1 and 1437 cm −1 , indicating the formation of carboxylate during extrusion. In addition, the puffed infant rice cereal exhibited firm diffraction peaks at the diffraction angles of 7.4°, 12.5° and 20.5°, indicating that a certain amount of starch changed from type A to type V. Furthermore, the digestive rate of puffed infant rice cereal was higher than that of commercial infant cereal (90.21 versus 86.96%, respectively; p < 0.05). Altogether, our findings reveal that the developed puffed infant rice cereal meets the standards set by the Codex Alimentarius Commission (CAC; 74-1981).

Fixation is one of the critical steps in tea processing and can cause various physico-chemical changes, thus affecting tea quality. There are many tea processing techniques, but their influence on quality remains unclear. Here, we studied the impact of different fixation methods, including for 6 or 10 min by machine, by iron pan, or by boiling water, on the biochemical characteristics of hawk tea. The results showed that tea fixation technique had a significant influence on the sensory quality, biochemical components, and antioxidant activity of the tea. Compared to other fixation techniques, fixation by boiling water produced a more nutritious hawk tea with stronger DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity (EC 50  = 6.56 μg/mL). Processing with boiling water also resulted in a better sensory quality with a unique sweet aftertaste. This tea also contained more polyphenols (19.60%), total amino acids (21,219 mg/100 g), essential amino acids (10,564 mg/100 g), and trace elements (5873.13 mg/kg). These results can guide the development of hawk tea products.