Journal of Food Process Engineering最新文献

Tea is an important industrial crop. It is the second most popular among all the drinks. The drying operation in the tea industry fulfills the aim of enzyme inactivation and reducing the moisture content to the desired level. The energy consumption in drying operation in the tea industry is mostly in the form of thermal energy. Drying consumes a greater amount of energy than other processes in tea industries. Thermal energy needs are met mainly through fossil fuels. Renewable energy sources such as bioenergy and solar energy are also being adopted but at the minute level. Further, addressing problems such as stewing and case hardening (arises due to improper drying conditions) during drying is necessary to avoid quality loss. In this study, mass transfer modeling of drying of crush tear curl (CTC) tea particles is conducted considering natural convection around the tea particle. A finite difference method with an explicit scheme is used to solve the equations for mass transfer modeling of drying. The effect of drying air temperatures on moisture content, moisture ratio, and drying rates are computed. Drying air temperatures such as 80, 90, and 100°C have not shown effective drying. However, drying at air temperatures of 110, 120, and 130°C are recommended for drying times of 1500 s, 1200 s–1500 s, and 1200 s, respectively. Additionally, the effect of the size of the particles is studied and the lower size of tea particles is recommended for better drying characteristics. The current drying model can be used for single tray/conveyor dryers and indirect natural convection single tray solar dryer.

Practical applications

The present research work demonstrates the important information for the hot air drying of CTC tea particle in single tray dryer. The drying modeling results can be used to set the proper temperature level of drying air being sent inside the dryer to avoid the under and over-drying of tea particle and achieve the desired level of moisture content in the tea particle. Thus, the present study helps in deciding drying conditions such as drying temperature, drying duration for CTC tea particle in single tray dryer, slow speed conveyor dryer, and also in indirect natural convection single tray solar dryer.

Microalgae are a high-potential source of biomolecules. Therefore, extracting bioactive components from microalgae with efficient and green extraction techniques is an important objective in many research. Cavitation-based extraction is gaining widespread attention as an environmentally friendly method due to its reduced energy and solvent consumption, enhanced extraction yield, improved extract quality, and reduced extraction time to extract bioactive products. This study aims to examine and optimize the extraction method for bioactive products from Chlorella vulgaris using Cavitation-based techniques compared with the traditional method to enhance the efficiency of extracting liquid extract. This experiment examined the extraction of bioactive components using various extraction methods, including Maceration, ultrasound-assisted extraction (UAE) (2–8 min) and hydrodynamic cavitation extraction (HCE) (1–5 min) was investigated regarding the extract's minerals, vitamins, amino acids, phytohormones, and total carbohydrates. The experimental design followed a response surface methodology to assess the effects of ultrasound-assisted and hydrodynamic cavitation extraction of liquid extract. The optimum time for maximum content of bioactive components using UAE and HCE was obtained at 7.87 and 1.76 min, respectively. This study showed that in comparing the three methods, Maceration (ME), UAE, and HCE, the UAC method was more useful and had a shorter extraction time compared with the ME and HCE methods for extracting bioactive products from C. vulgaris. Also HCE was more useful compared with the ME method. These results demonstrate that the cavitation-based extraction methods are more effective and efficient than traditional extraction methods.

Practical applications

In order to increase the content of flavoring components and nutrients in the stock, effects of microwave (MW) combined with ultrasonic pretreatment on water-soluble proteins, flavor nucleotides, volatile gas constituents and sensory evaluation in the stewed stock were explored. The results showed that, compared with the control group (CK), MW, and ultrasonic (US) pretreatment could significantly promote the degradation of nucleotides and form a large number of 5′-flavor nucleotides. The combined treatment of MW and US promoted protein hydrolysis and increased the content of water-soluble protein. The microwave combined ultrasonication pretreated stew stock had the brightest color and the overall sensory score was better than that of the CK. In addition, GC–MS analysis showed that a total of 49 volatile substances were detected in the stock samples. After microwave combined ultrasonication pretreatment, the relative contents of aldehydes and alcohols in the stock increased significantly. The sensor response value of the electronic nose was the highest, indicating that the intensity of flavor characteristics increased. Therefore, MW combined with ultrasonic pretreatment can effectively promote the formation and dissolution of nutrients, and increase the content of flavorful nucleotides and volatile gases.

Practical application

This study provides a novel processing method for traditional stewed stock. Ultrasonic combined with MW treatment can quickly degrade the protein in the raw material and dissolve it into the stock. At the same time, it promotes the formation of flavor nucleotides and accelerates the Maillard reaction to produce more flavor substances. The technology has the advantages of short processing time, environmental protection and safety. It can be used as a potential pretreatment technology to regulate the flavor of stock-soup.

The objective of the study is to develop and characterize biodegradable monolayer and bilayer films using collagen extracted from tilapia skin and scales (Oreochromis sp.) with chitosan in combination with biodegradable polyester; polylactic acid (PLA) or polycaprolactone (PCL). Collagen extraction was conducted with acetic acid (0.5 M). Monolayer films based on collagen and chitosan were formed by the casting process with a solution of chitosan (2% w/w) in 1.5% acetic acid, followed by the addition of skin collagen at concentrations of 0.5%, 1%, or 2% w/w, and dried at 45–50°C. The PLA and PCL films were made by compression molding. The films were characterized according to their appearance, structure, morphology, interaction with water, thermal stability, and mechanical and barrier properties. The results indicated that collagen from tilapia skin and scales yielded 36.5% and 2.57%, respectively. The results showed that adding chitosan increased the tensile strength but decreased the elongation of the films. An improvement in thermal stability was observed by increasing the proportion of collagen or chitosan, and it also influenced water solubility and water vapor permeability. Microscopy showed a crack-free interface between collagen and chitosan. The color of the films varied depending on the composition, highlighting the influence of chitosan in yellow and reddish tones. The bilayers with PLA had lower water vapor permeability and higher gloss compared to those with PCL. Finally, the developed films showed promising properties for their application in food packaging and promote the use of fishery waste.

Practical applications

The study aims to develop and characterize biodegradable monolayer and bilayer films using collagen extracted from tilapia skin and scales (Oreochromis sp.) combined with chitosan and biodegradable polyester such as polylactic acid or polycaprolactone. The practical applications of this research span a wide range of industrial fields. For instance, monolayer films could be used as sustainable food packaging, offering enhanced barrier properties and biodegradability, thus reducing the environmental impact of conventional packaging. Furthermore, bilayer films could find applications in the healthcare industry, such as controlled-release drug patches or dressings leveraging the antimicrobial properties of chitosan. This research also provides valuable insights into improving the mechanical, thermal, and barrier properties of biodegradable films, potentially leading to the production of more efficient and versatile materials for a variety of industrial applications.

Multispectral imaging (MSI) is an emerging technique that ranges from light spectrum of UV–NIR (405–970 nm) used for rapid determination of phenolic contents. The current study focuses on the determination of total phenolic content (TPC) in a fast and non-invasive way in hot-air dehydrated Lentinus edodes. The spectral information of MSI has been combined with various chemometrics like partial least squares (PLS), back propagation neural networks (BPNN), and least squares-support vector machines (LS-SVM) for the quantitative prediction of phenolic contents. Fresh mushrooms possessed 1.49 and 1.73 GAE g kg⁻¹ TPC in processed samples at 10% moisture content. Comparing models, PLS acquired significant R_p with a lower RMSEP of 0.9980 and 0.1039 and was considered an outstanding algorithm, followed by LS-SVM of 0.9777 and 0.1417 coefficient of determination and error of prediction data set, respectively. It is concluded that MSI spectroscopy produces highly significant results to determine functional food properties in a rapid and non-destructive way. The present study will provide a strong platform for the fast online determination of phenolic profile of agricultural commodities.

Practical applications

Utilization of spectroscopy for non-destructive detection of phenolic contents is defined through the combination of chemometrics with spectra of multispectral imaging system and emphasizes control processing of postharvest horticulture produces. Prediction results R² above 80% describe that these chemometrics are successfully capable of estimating total phenolic contents in control processing for quality preservation.

The rapid fouling and bacterial contamination of equipment, heat exchangers, and pipelines are major concerns in food manufacturing plants. The process of cleaning-in-place (CIP) in the food manufacturing industry involves hazardous chemicals such as sulfuric acid, chlorine, sodium hydroxide, and potassium hydroxide. This study aims to investigate the cleaning efficiency of a novel environment-friendly solution, plasma-activated water (PAW), for removing dairy and plant-based fouling and for biofilm reduction. PAW was produced by exposing water to plasma, which is a partially ionized gas generated by applying electricity to air. PAW prepared in this study had a pH, electrical conductivity (EC), and oxidation–reduction potential (ORP) of 2.5 ± 0.1, 1170. 1 ± 202.2 μS/cm, and 589.0 ± 2.4 mV, respectively. Holding PAW at different temperatures (20–75°C) did not change pH, ORP, and EC significantly, while nitrite and nitrate concentrations in PAW did not show a consistent trend with temperature. The treatment time and temperature of PAW were optimized for cleaning fouled coupons (stainless-steel type 304 and 316) using model fouling fluids (MFF) with dairy (whey) and plant-based (oat) proteins using full-factorial design. The optimized PAW combinations (15 min/75°C and 5 min/75°C) were found to be as effective for fouling removal as compared to CIP controls (conventional caustic and acid solutions). Optimized PAW also showed significant biofilm reduction of Listeria innocua on stainless-steel coupons with/without fouling, with at least 4.4 log and 4.0 log reductions in L. innocua biofilms when attached to MFF-whey and MFF-oat, respectively.

Practical applications

Plasma-activated water (PAW) can inactivate a wide spectrum of microorganisms on various food and food contact surfaces. We propose the use of environment-friendly plasma-activated water (PAW), which can be prepared on-site and on-demand for cleaning-in-place (CIP) operations in the food industry. The results of this study suggest the potential of PAW as a promising CIP alternative for cleaning and sanitizing surfaces soiled by fouling deposits in dairy and plant-based industries.

The effects of ultrasound (US), ultrahigh pressure (UP), cold plasma (CP), and high pressure and pulsed electric fields (PEF) pretreatments were evaluated for drying characteristics, bioactive components, and pectin properties of jujube slices during microwave coupled with pulsed vacuum drying (MPVD). US, CP, and PEF reduced drying time by 18.75%, while UP reduced it by 6.25%. Samples treated with US and PEF showed improved color and rehydration (345.11%, 319.24%), with SEM revealing larger pores post-pretreatment. PEF-treated jujube had highest phenol (16.95 mg GAE/g DW) and water-soluble pectin(WSP) (43.71 mg/g AIR), correlating positively with rehydration (r = 0.67). CP had highest flavonoid content (17.01 mg RE/g DW) and US showed highest antioxidant activity (DPPH 80.57%, ABTS 89.65%). Chelate-soluble pectin (CSP) Sodium carbonate-soluble pectin (NSP) was positively correlated with hardness (r = 0.71, 0.69). These findings suggest pretreatments improve drying efficiency, nutrient retention, and pectin functionality in jujube products.  

Practical Applications

Drying for jujube (Ziziphus jujuba Mill.) is the most common method of processing and ensure the sale. Three kinds of non-thermal processing pretreatment method (ultrasound, ultrahigh pressure, and cold plasma) combined with novel drying method, microwave coupled pulsed vacuum drying (MPVD) was studied in the application on the dehydration of jujube slice in this paper. The drying characteristics and pectin properties of winter jujube were analyzed and treated by MPVD compared with freeze drying and hot air drying, for both technological research and processing practice. The drying kinetics, bioactive compounds, antioxidant capacity, sensory attributes, and pectin properties were also used as descriptors in order to promising dehydration method for obtaining high value-added jujube products. Moreover, the relationship between the cell wall pectin and the phenols, hardness and crispness were analyzed, which give a new insight to study the changing scheme in the nutrients and the texture during the dehydration for fruits and vegetables.

This study examined the structural characterization and in vitro digestibility of rice starch processed with the combination of ultra-high pressure homogenization (UHPH), debranching, and temperature-cycled crystallization under various pressures (0–160 MPa). After UHPH treatment, the degree of branching (DB) of processed starches (0.65%–2.03%) was lower than that of the native rice starch (NS, 2.96%). Assessment of chain length distribution suggested that the considerable amylose was produced after treatments. Processed starches exhibited an irregular fragmented structure, and the crystalline structure was transformed from A-type (native rice starch) into B + V-type (processed starches). Moreover, the relative crystallinity (RC) and the absorbance ratio of 1047/1022 cm⁻¹ (R_1047/1022) of processed starches decreased from NS (RC, 22.99%; R_1047/1022, 0.79) to 13.47%–18.21% (RC) and 0.51–0.78 (R_1047/1022), respectively. Iodine binding curves revealed that processed starches possessed the higher degree of polymerization (DP). Furthermore, the contents of slowly digestible starch (SDS) and resistant starch (RS) increased in all processed starches, and the RS content of starch treated under 160 MPa (35.33%) was notably greater than that of native starch (9.37%). These results suggested that the UHPH can be used as a pretreatment strategy to reduce the digestibility of starch products.

Practical applications

UHPH pretreatment disrupts starch molecular chains to produce the large amounts of short linear amylose. Debranching followed by temperature-cycled crystallization can increase the content of resistant starch (RS), yielding a raw material suitable for boosting the health of the digestive system and overall health. Therefore, UHPH pretreatment has a high application value in the field of starch modification.