The need for enhancing microbial safety and quality of foods without compromising the nutritional, functional, and sensory characteristics has created an increasing interest across the globe in innovative technologies for food preservation [1]. Emerging food processing technologies, such as physical, chemical, and biological methods, have been advanced by the food industry and academia during the last few decades. This is in an attempt to meet the need of producing safe foods of high quality. These emerging technologies could significantly contribute to the production of microbiologically safe foods with high quality [2]. Moreover, the production will be of shorter processing time, reduced operational cost, and environmental friendship compared to the conventional food processing technologies, which will eventually benefit the food industry. However, each emerging technology has its own limitation. Therefore, future research should be conducted in order to apply these technologies at a commercial level. With this background, many researchers have worked toward the development and optimization of several emerging food processing technologies. The special issue consists of six research papers that were selected from various submissions. While these papers may not fully cover the topics mentioned above, they represent the rich and many-faceted knowledge.
Shimanouchi et al. conducted the hydrolysis of disaccharides by using a microcapillary system under hydrothermal conditions (up to 190°C at 10 MPa and pH 4–11). The hydrolysis reaction showed a sigmoidal progression with time, especially under alkaline conditions. An analysis using a kinetic model yielded a reaction induction period. The specific pH value (pHamb) at the induction time, which is the pH value corresponding to the progression of disaccharide hydrolysis, was peculiar to each disaccharide. Finally, the calculation of the electron density around the oxygen atom of the glycosidic bond between the saccharides was found to roughly predict the pHamb value required for the progression of the hydrolysis.
Some importers of marine products have practiced the fraud of artificially injecting water into Octopus minor for the purpose of increasing their weights prior to the freezing process. These rampant practices have recently become a serious social issue, and they threaten public health. Lee et al. developed a nondestructive method for verifying adulterated Octopus minor through measuring dielectric properties by using the coaxial probe method. The dielectric loss factor (ε″) values of the adulterated octopuses were much lower than normal octopuses. The ε″ values from the normal frozen octopus were significantly different from the adulterated and imported frozen octopuses. Additionally, the ε″ values from the adulterated frozen octopus group, whose weight gain rate was less than 20%, were significantly different from other adulterated octopus groups with a higher weight gain rate than 20%. The ε″ values from the adulterated frozen octopus groups with a range of weight gain rate between 20% and 30% were quite similar to the imported frozen octopuses. Therefore, it was found that the measurement of the ε″ values from an Octopus minor has a great possibility to distinguish between normal frozen octopuses and artificially water-injected frozen octopuses.
Mineral oil hydrocarbon (MOH) contamination in food has become a major concern in the past decade. This is after it was brought to light that the substances might potentially be harmful to human health. Ethylene vinyl alcohol copolymer (EVOH) is a key material of interest as a functional barrier against substances migrating from recycled paperboard. This is due to its outstanding barrier properties. Maes et al. reported that all films containing 3 or 5 µm EVOH were found to be good barriers, showing no breakthrough values over 1% of the initial concentration found in the paperboard. Moreover, they could easily compete with monolayer polyethylene terephthalate (PET, 12 µm). The multilayer with 3 µm polyamide 6/6.6 copolymer (PA 6/6.6) showed higher breakthrough values for both the 4-methylbenzophenone (MBP) and di-n-propyl phthalate (DPP) than the other materials, however, below the 1% threshold value. However, anthracene (ANT) showed substantial breakthrough values of about 2%, indicating that PA 6/6.6 might not offer enough protection against low-weight mineral oil aromatic hydrocarbon (MOAH) components.
Even though liposomes have been used as nutrient delivery carriers in the cosmetic, food, and pharmaceutical industries, they still suffer from the critical issue caused by the use of halogenated solvents, such as chloroform, which may be harmful to humans. Yang et al. screened nonhalogenated solvents as candidate substitutes for the chloroform based on their physicochemical properties. They also prepared combined mixtures using various ratios of each candidate to obtain physicochemical properties similar to the chloroform. Based on the results of random combination trials with numerous candidates, the ethyl acetate : n-hexane = 4 : 1 (v/v) was selected to be the optimum ratio because it could form stable inverted micelles and a transparent liposome solution without phase separation. The ethyl acetate and n-hexane mixture are a potential substitute for chloroform, which may resolve the concerns regarding the toxicity of residual halogenated solvents in lipid nanovesicles.
Choi et al. expressed α-glucanotransferase from Bacteroides thetaiotaomicron (BtαGTase) in Escherichia coli and characterized. The BtαGTase catalyzed the transglycosylation reactions that produced only glycosyl or maltosyl transfer products, which are preferable for the generation of transglycosylated products with high yields. The 1-deoxynojirimycin (DNJ) glycosylation product G1-DNJ was generated using the BtαGTase, and the inhibitory effect of G1-DNJ was analyzed. A kinetic study of the inhibition revealed that the G1-DNJ inhibited α-glucosidase to a greater extent than DNJ did. However, it did not show any inhibitory effects toward α-amylase, suggesting that G1-DNJ is a potential candidate for the prevention of diabetes.
Joung et al. studied in vitro biodegradation of Bombyx mori silk fibroin (SF) by using food-grade proteolytic enzymes to replace acid hydrolysis. Based on the residual protein quantity and yield of amino acids (AAs) after enzymatic hydrolysis, they evaluated the proteolytic enzyme process of the SF. FoodPro and Alcalase that are classified as alkaline proteases were selected as two of the best candidate enzymes for the hydrolysis of SF. A 2-stage enzymatic treatment by using a combination of FoodPro and Flavourzyme in a sequence for a reaction time of 6 hours was developed to enhance the efficiency of the proteolytic process. The regenerated SF and its enzymatic hydrolysates were characterized by performing a UV-visible spectra, gel electrophoresis, and size-exclusion chromatography analyses. In the 2-stage treatment using FoodPro initially and Flavourzyme thereafter, the aggregates and high molecular weight proteins of the SF were dissociated and degraded into the low-molecular-weight proteins/peptides (10–15 kDa and 27 kDa). SF hydrolysates, as functional food, might enzymatically be produced by using the commercial food-grade proteolytic enzymes.
By compiling these papers, we hope to enrich our readers and researchers with respect to the most recent progresses in the field of innovative strategies and emerging technologies for food safety.
Conflicts of Interest
The editors declare that they have no conflicts of interest regarding the publication of this special issue.
Acknowledgments
The guest editors would like to thank all the authors for their contribution to this special issue and appreciate all reviewers for their time and valuable comments to improve the quality of these papers.
Kyung-Min Park
Sang-Hyun Park
Toshinori Shimanouchi