Applications In Food Technology Research Articles

Morphological and ultrastructural changes in Lactobacillus plantarum B21 as an indicator of nutrient stress

This study investigated the effect of nutrient stress on cell viability and growth, bacteriocin activity, acid production, morphology and ultrastructure of Lactobacillus plantarum B21. The aim was to ascertain if this species’ viability in food applications could potentially be controlled/improved by initial culture conditions. Both glucose and Tween 80 were found to have statistically significant effects on cell viability, as well as pH and bacteriocin production. Scanning and transmission electron microscopy revealed that nutrient availability was also associated with changes in cell size and shape. Control cells displayed a regular, smooth, rod-shaped morphology with well-defined cytoplasmic contents, equal distribution of nuclear material and an intact cell-wall. In contrast, nutrient-stressed cells became irregular, varied in size and shape and had a ruffled, but intact, cell membrane with dense, fibre like protrusions. The absence of glucose in growth media resulted in a coccoid cell shape, whereas the absence of Tween 80 resulted in the formation of filamentous, rod shaped cells. This study proposes nutrient levels could be used as means of controlling the length to diameter ratio and shape of Lactobacillus plantarum B21 in order to produce robust, functional bacterial cells that could be used for applications in food technology.

Theoretical study of the arabinan hydrolysis by an inverting GH43 arabinanase

The endo-1,5-α-L-arabinanases (ABNases) belong to the glycoside hydrolase family 43 (GH43) and hydrolyse α-1,5-arabinofuranosidic bonds in arabinose-containing polysaccharides by an inverting mechanism. ABNases are key enzymes involved in hemicellulose degradation with various applications in food technology, organic synthesis and biofuel production. Here, the reaction mechanism of the Geobacillus stearothermophilus GH43 ABNases has been investigated using density functional theory method. To probe the role of the pKa modulators (Ser164 and Tyr229) in the reaction, two different orientations of a catalytic acid (Glu201) with respect to the position of these residues are considered. The results show that the orientation involving a hydrogen bond network (Ser164•••Glu201•••Tyr229) is energetically more favourable, compared to the other one (Ser164•••Glu201), with a barrier of 13.6 kcal mol−1, consistent with the experimental data. Our calculations also give support to a single displacement mechanism proposed in the literature where the protonation of glycosidic bond and a nucleophilic attack by a catalytic water occur in a concerted but asynchronous manner.

Evaluation of the Food Sniffer electronic nose for assessing the shelf life of fresh pork meat compared to physicochemical measurements of meat quality

In food technology applications, electronic noses have been used on the on-line control of different processes. In this study, assessment of shelf life of fresh pork meat that had been stored under refrigeration in aerobic conditions using an electronic nose pocket device was tried. The physicochemical, sensory, and microbiological parameters of white female pork tenderloin, stored at 4 °C for 7 days, were related to the response obtained with an electronic nose device (Food Sniffer®) (FS) to validate its possible use as a rapid method of determining the shelf life of meat. The response of the electronic nose device, qualitatively validated, was significantly correlated with some parameters as microbiological counts or sensory parameters; unfortunately, tight quantitative limits between FS response and some analytical results as biogenic amine content could not be related.

A novel protein tyrosine phosphatase like phytase from Lactobacillus fermentum NKN51: Cloning, characterization and application in mineral release for food technology applications

A novel protein tyrosine phosphatase like phytase (PTPLP), designated as PhyLf from probiotic bacterium Lactobacillus fermentum NKN51 was identified, cloned, expressed and characterized. The recombinant PhyLf showed specific activity of 174.5 U/mg. PhyLf exhibited strict specificity towards phytate and optimum temperature at 60 °C, pH 5.0 and ionic strength of 100 mM. Km and Kcat of PhyLf for phytate were 0.773 mM and 84.31 s−1, respectively. PhyLf exhibited high resistance against oxidative inactivation. PhyLf shares no homology, sans the active site with reported PTLPs, warranting classification as a new subclass. Dephytinization of durum wheat and finger millet under in vitro gastrointestinal conditions using PhyLf enhanced the bioaccessibility of mineral ions. Probiotic origin, phytate specificity, resistance to oxidative environment and gastric milieu coupled with ability to release micronutrients are unique properties of PhyLf which present a strong case for its use in ameliorating nutritional value of cereals and animal feed.

The Impact of Microalgae in Food Science and Technology

AbstractMicroalgae (including cyanobacteria) are promising organisms for sustainable products for use as feedstocks for food, feed, fine chemicals, and biofuels. They can synthesize a broad range of products with medium‐ to high‐value market price such as β‐1,3‐glucan polysaccharide, single‐cell‐protein, carotenoids and phycobilin pigments, and long‐chain polyunsaturated fatty acids that are commercialized in the food industry as dietary supplements and functional foods, in the pharmaceutical and chemical industries as cosmaceuticals and flavorants, and in the therapeutic field as nutraceutical compounds. These microorganisms are also exceptional producers of omega‐3 and omega‐6 fatty acids such as eicosapentaenoic, docosahexaenoic, and arachidonic acids that have been linked to several human health benefits. The aim of this paper is to review the main existing high‐value products that can be derived from microalgae with a particular focus on food science and technology applications. It also describes the gross and fine chemical composition of various algal species and details the nutritive importance of selected constituents. Finally, nutritional quality standards and legislative provisions to ensure food safety in the use of algal biomass are presented.

Kinetic and Thermodynamic Analysis of Two Carboxymethylcellulases from Macrotermes subhyalinus Little Soldier

Optimization of thermal processes relies on adequate degradation kinetic models to warrant food safety and quality. The knowledge on thermal inactivation of enzymes is necessary to allow their proper utilization in food industry and technology applications, enabling the reduction of heating times and optimization of heating temperatures. In this work, the kinetic of thermal inactivation was studied for the previously characterized carboxylmethylcellulases Ab-CX1 and Ab-CX2 from Macrotermes subhyalinus little soldier. Samples of carboxymethylcellulases were treated at different time-temperature combinations in the range of 5-60 min at 50-65°C and the kinetic and thermodynamic parameters for carboxymethylcellulases were calculated. Results showed that inactivation followed a first-order reaction with k-values between 0.0103 ± 0.0003 to 0.1217 ± 0.0005 and 0.0149 ± 0.0007 to 0.0416 ± 0.0003 min-1 for Ab-CX1 and Ab-CX2, respectively. At high temperatures, Ab-CX2 was less resistant, with a significant decrease in residual activity compared to Ab-CX1. The D- and k-values decreased and increased, respectively, with increasing temperature, indicating faster inactivation of carboxymethylcellulases. Activation energy (Ea) and Z-values were estimated to 76.74 ± 1.98 kJ.mol-1 and 24.21 ± 1.92 °C for Ab-CX1, 62.80 ± 2.05 kJ.mol-1 and 33.33 ± 2.78 °C for Ab-CX2. Thermodynamic parameters (ΔH#, ΔS# and ΔG#) were also calculated. The high value obtained for the variation in enthalpy of activation indicates that a high amount of energy is required to initiate denaturation, probably due to the molecular conformation of carboxymethylcellulases. All results suggest that both carboxymethylcellulases are relatively resistant to long heat treatments up to 50°C.

Influence of extraction variables on the structure and physical properties of salmon gelatin

This work focuses on investigating the effect of extraction conditions (pH and time) on the biochemical and physical properties of salmon gelatin (SG).SG was extracted from salmon skins under different pH and time conditions at 60 °C. The characterization of the material considered proximate composition, amino acid profile, molecular weight (MW), gel strength, X-Ray diffraction, thermal properties, dynamic mechanical properties and dynamic vapour sorption analysis.Results showed that higher protein content was obtained with extraction condition pH5/2h, while lower protein content was obtained at condition pH3/5h. Extraction performed at pH5 produced SG with MW > 120 kDa, while processing condition at pH3 resulted in MW bands distributed between 20 and 100 kDa. Higher contents of proline and hydroxyproline were detected in SG with high MW. This behaviour was directly correlated with gel strength and thermo-mechanical properties: higher gel strength and E’ modulus were observed in SG with high MW, suggesting higher amount of triple helical structures in gelatin matrix. This was also supported by higher values of tanδ detected as the MW of SG decreased. This may be related with decreasing the crystalline fraction of SG. Thermal properties revealed no significant differences in melting temperature and glass transition temperature values among samples. The melting energy was significantly lower for SG with lower MW. This was confirmed by X-Ray diffraction where the intensity of the diffraction peak at ∼2θ = 8° significantly decreased for SG extracted under more aggressive conditions. Finally, gelatin extracted under mild conditions showed higher moisture content, which was in agreement with higher amounts of triple-helix structures.Our results suggest the possibility to modulate the physical properties of SG by tuning the extraction process to obtain tailored gelatin structures for high-value applications in food technology, tissue engineering and biomedicine.

Pulsed Electric Fields Pretreatments for the Cooking of Foods

Development of the concept of electroporation opened new perspectives for promising applications in food technology. Treatment of foods with pulsed electric fields (PEFs) allows facilitation of different food transformation operations (extraction, expression, osmotic treatment, drying, and freezing) with minimal energy consumptions and better retention of flavor, color, and preservation of nutritional properties of foods. This work shortly reviews the effects of PEF on the biological cells and food products and gives the examples of PEF-assisted techniques. The PEF protocol, power consumption, and existing small- and large-scale electroporation systems are presented. Some examples of PEF-assisted processing of meat, fish, and fat frying are discussed. The main principles of PEF-assisted cooking and kitchen operations are also discussed. The variants of PEF-assisted non-thermal cooker and PEF/ohmic thermal cooker are presented. It is speculated that PEF allows more homogeneous treatment of foods as compared to the conventional methods of thermal cooking. The PEF-assisted cooking can be faster and more effective for nutrient retention and sensory qualities of foods. Moreover, the PEF treatment can be used for producing the types of the products of fresh/natural quality and new tastes. The recent examples of PEF-assisted processing of meat and fish, assistance of frying, and commercial-scale processing are also presented and discussed.

A Review on the toxicology and dietetic role of bacterial cellulose.

Bacterial cellulose (BC) is a biopolymer synthesized by certain acetic acid bacteria strains. The safety of BC regarding its potential use in food applications is here reviewed. The acute, sub-acute and subchronic oral toxicity assays showed that consumption of BC had no adverse effects in rats. Several studies demonstrated that BC is not genotoxic, did not induce chromosomal aberrations in CHO cells under both non-activating and metabolic activating conditions, is inactive in the in vitro Rat Primary Hepatocyte Unscheduled DNA Synthesis Assay, had no reproductive toxicity in mice and exerted no embryotoxicity and teratogenicity effects in rats.Several studies on the BC in biomedical applications further reinforces its safety: a primary eye and dermal irritation studies in the rabbit showed that BC was non-irritating. The inflammatory reaction to subcutaneously implanted BC has been evaluated in animal models and for different periods of time, demonstrating that BC is biocompatible and does not trigger a harsh inflammatory reaction.Altogether, and considering its longstanding history of human consumption in Asian countries, as well as its utilization in biomedical devices, it may be concluded that BC is safe for applications in food technology.

Purification and Characterization of a Novel Anti-Campylobacter Bacteriocin Produced by Lactobacillus curvatus DN317.

The lactic acid bacteria (LAB) microbiota of Saudi chicken ceca was determined. From 60 samples, 204 isolates of lactic acid bacteria were obtained. Three isolates produced antimicrobial activities against Campylobacter jejuni, Listeria monocytogenes, and Bacillus subtilis. The isolate DN317, which had the highest activity against Campylobacter jejuni ATCC 33560, was identified as Lactobacillus curvatus (GenBank accession numbers: KX353849 and KX353850). Full inhibitory activity was observed after a 2-h incubation with the supernatant at pH values between 4 and 8. Only 16% of the activity was conserved after a treatment at 121°C for 15min. The use of proteinase K, pepsin, chymotrypsin, trypsin, papain, and lysozyme drastically reduced the antimicrobial activity. However, lipase, catalase, and lysozyme had no effect on this activity. The active peptide produced by Lactobacillus curvatus DN317 was purified by precipitation with an 80% saturated ammonium sulfate solution, and two steps of reversed phase HPLC on a C18 column. The molecular weight of this peptide was 4448Da as determined by MALDI-ToF. N-terminal sequence analysis using Edman degradation revealed 47 amino acid residues (UniProt Knowledgebase accession number C0HK82) revealing homology with the amino acid sequences of sakacin P and curvaticin L442. The antimicrobial activity of the bacteriocin, namely curvaticin DN317, was found to be bacteriostatic against Campylobacter jejuni ATCC 33560. The use of microbial antagonism by LAB is one of the best ways to control microorganisms safely in foods. This result constitutes a reasonable advance in the antimicrobial field because of its potential applications in food technology.

Optimization of Levan Production by Cold-Active Bacillus licheniformis ANT 179 and Fructooligosaccharide Synthesis by Its Levansucrase.

Fructooligosaccharides (FOS) and levan attract much attention due to a wide range of applications in food technology and pharmaceutical and cosmetic industry. Bacillus licheniformis ANT 179, isolated from Antarctica soil, produced levansucrase and levan in a medium containing sucrose as carbon substrate. In this study, characterization of levansucrase and production of short-chain FOS and levan were investigated. Temperature and pH optimum of the enzyme were found to be 60°C and pH 6.0, respectively. The optimization of fermentation conditions for levan production using sugarcane juice by response surface methodology (RSM) was carried out. Central composite rotatable design was used to study the main and the interactive effects of medium components: sugarcane juice and casein peptone concentration on levan production by the bacterium. The optimized medium with sugarcane juice at 20% (v/v) and casein peptone at 2% (w/v) was found to be optimal at an initial pH of 7.0 and incubation temperature of 35°C for 48h. Under these conditions, the maximum levan concentration was 50.25g/L on wet weight basis and 16.35g/L on dry weight basis. The produced inulin type FOS (kestose and neokestose) and levan were characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) analysis. The study revealed that the levansucrase could form FOS from sucrose. The locally available low-cost substrate such as sugarcane juice in the form of a renewable substrate is proposed to be suitable even for scale-up production of enzyme and FOS for industrial applications. The levan and FOS synthesized by the bacterium are suitable for food applications and biomedical uses as the bacterium has GRAS status and devoid of endotoxin as compared to other Gram-negative bacteria.

Separation and quantification of milk casein from different buffalo breeds.

Understanding the milk protein expression profile in different buffalo breeds plays an important role in improving hybrid selection and determining the effects on milk protein synthesis. The aim of this research is to compare the differences in milk protein content, composition and distribution between River buffalo and their crossbreeds for hybrid screening. Four groups of milk samples that included Nili-Ravi (N), Murrah (M), a Nili-Ravi-Murrah crossbreed (M-N), and a crossbreed of river buffalo with local swamp buffalo (C) were collected. The protein composition of the buffalo milk was determined by RP-HPLC. A gel-based proteomic approach consisting of two-dimensional gel electrophoresis coupled with mass spectrometry was utilised for the detailed protein characterisation of milk from different breeds. The results of this analysis showed that the river/swamp buffalo crossbreed (C) displayed the highest content of total protein (4·46%) and κ-casein (11·14%) but the lowest content of α-lactalbumin (6·79%). By selecting 23 different protein spots among the four types of milk that contained the most spots corresponding to κ-casein, β-casein and αs1-casein, correlations between the crossbreeds, protein polymorphism and phosphorylation could be made. The results of this study indicate that crossbreeding a swamp buffalo with a river buffalo has a notable effect on the protein content and composition that may be exploited for producing high-quality raw milk in food technology applications and dairy food production.

Antioxidant and Anti-Inflammatory Properties of Widely Consumed Date Palm (Phoenix Dactylifera L.) Fruit Varieties in Algerian Oases

The purpose of this study was to estimate the antioxidant and anti-inflammatory activities of methanolic extracts of date palm fruits grown in Algeria. Four in vitro methods were employed to evaluate the antioxidant activity (AA), namely β-carotene-linoleic acid system, phosphomolybdenum method, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and Ferric-Reducing Antioxidant Power assay. The anti-inflammatory activity was carried out using carrageenan-induced edema model. The extracts were found to be a rich source of polyphenols, flavonoids and flavonols. The methanolic extract of Ali Ourached cultivar showed the highest AA for the four methods cited previously (76.85%, 90.25 μmol of ascorbic acid/g of extract, 206 µg/mL and 56.04 μmol Fe (II) ∕ 100 g DW, respectively). Anti-inflammatory findings revealed noticeable reduction of paw volume ranging from 35.64 to 67.56% as a response to oral administration of 250 mg/kg dose of methanolic extracts. This study constitutes an endeavor for understanding the bioactive phytochemical variability in date palm fruit cultivars and corresponding antioxidant and anti-inflammatory activities. Practical Applications In this study, the biological potentials of methanolic extracts of date palm fruits (Phoenix dactylifera L.) were evaluated. The date cultivars could potentially be considered as a functional food and could be useful as a good source of natural antioxidant compounds with possible applications to reduce oxidative stress and treatment of chronic inflammatory pathologies. The results suggest that date palm fruits contain potent antioxidant and anti-inflammatory properties that can find application in food science, food technology and nutrition.

Extraction of sporopollenin exine capsules from sunflower pollen grains

A simple extraction process was developed to isolate sunflower sporopollenin exine capsules (SECs). The sunflower SECs holds significant potential as biomaterial for applications in drug delivery, cosmetics, and food technology.

Tubular cellulose/starch gel composite as food enzyme storehouse

The objective of this study was to produce a composite biocatalyst, based on porous cellulosic material, produced after wood sawdust delignification (tubular cellulose; TC) and starch gel (SG), for the development of bioprocesses related to enzyme applications. The composite biocatalyst was studied by Scanning Electron Microscopy to observe the SG deposition in the TC pores, and porosimetry analysis to determine the average pore diameter and surface area. The deposition of SG into the TC tubes provided a TC/SG composite with reduced pore sizes. X-ray powder diffractometry showed a decrease of crystallinity with increased SG ratio in the composite. The composite was used as an insoluble carrier for entrapment of the dairy enzyme rennin, leading to the production of an active biocatalyst for milk coagulation (initiation of milk clotting at about 20min and full coagulation at about 200min), creating perspectives for several applications in food enzyme research and technology.

Erratum to: Characterization of chicken waste fat for application in food technology

Erratum to: Characterization of chicken waste fat for application in food technology

Development and characterization of biodegradable chitosan films containing two essential oils

Active biodegradable films from chitosan containing 10% to 30% w/w of citronella essential oil (CEO) and cedarwood oil (CWO) were developed by casting and solvent-evaporation method, and their physical, mechanical and thermal properties were investigated. Possible interactions between the chitosan chains and the essential oils were confirmed using Fourier-transform infrared spectroscopy (FTIR). Various amounts of CEO or CWO had significant effects on the films’ mechanical properties, with the exception of 10% of CEO, which did not significantly affect the tensile strength of the films. The incorporation of the two tested oils provoked a remarkable reduction in the water-vapor permeability properties, with a decrease of about 63% when 30% CEO was added in chitosan films. Thermogravimetric analysis showed that degradation temperatures of the films containing CEO and CWO improved only slightly in comparison to control films without essential oils. FTIR spectra analysis provided some insights on the possible interactions between chitosan and the two essential oils used. This study suggests that active films can be developed by including CEO and CWO in a chitosan matrix. Such films can provide new formulation options for packaging industries in developing active packaging with potential food-technology applications.

Characterization of chicken waste fat for application in food technology

Chicken waste which mainly contains skin and depot fat can be used for extraction of edible fat. In this study physicochemical properties of chicken waste and its fat was determined. The content of fat, moisture, protein and ash in chicken waste was 38.92, 50.78, 8.93 and 1.28 %, respectively. Chicken waste fat (CWF) contained palmitic acid as the main saturated fatty acid and oleic and linoleic acid as the main unsaturated fatty acids. It contained considerably lower saturated fatty acids than beef tallow, lard and palm oil. The fatty acid composition of CWF was very similar to that of rice bran oil. CWF contained lower level of cholesterol (780 ppm) than tallow and lard. Phosphorus level of CWF was much lower than vegetable oils and it may be refined without degumming. The iron content of the CWF, however, was much higher than that reported for vegetable oils, which necessitates a careful bleaching of the fat. Iodine value and refractive index of CWF were lower than tallow, lard and palm oil but higher than that of cottonseed and rice bran oil. Free fatty acid content (0.62 %) and peroxide value (1.84 meq/kg) were found to be at acceptable levels. Melting point and solid fat content (SFC) of CWF at 10–35 °C were lower than those reported for tallow, lard and palm oil. CWF can be used for production of soft tub margarine and vanaspati.

Electroporation in food processing and biorefinery.

Electroporation is a method of treatment of plant tissue that due to its nonthermal nature enables preservation of the natural quality, colour and vitamin composition of food products. The range of processes where electroporation was shown to preserve quality, increase extract yield or optimize energy input into the process is overwhelming, though not exhausted; e.g. extraction of valuable compounds and juices, dehydration, cryopreservation, etc. Electroporation is--due to its antimicrobial action--a subject of research as one stage of the pasteurization or sterilization process, as well as a method of plant metabolism stimulation. This paper provides an overview of electroporation as applied to plant materials and electroporation applications in food processing, a quick summary of the basic technical aspects on the topic, and a brief discussion on perspectives for future research and development in the field. The paper is a review in the very broadest sense of the word, written with the purpose of orienting the interested newcomer to the field of electroporation applications in food technology towards the pertinent, highly relevant and more in-depth literature from the respective subdomains of electroporation research.

Application of Glass Transition in Food Processing

The phenomenon of glass transition has been employed to food products to study their stability. It can be applied as an integrated approach along with water activity and physical and chemical changes in food in processing and storage to determine the food stability. Also associated with the changes during agglomeration crystallization, caking, sticking, collapse, oxidation reactions, nonenzymatic browning, and microbial stability of food system. Various techniques such as Differential Scanning Calorimetry, Nuclear Magnetic Resonance, etc. have been developed to determine the glass transition temperature (Tg) of food system. Also, various theories have been applied to explain the concept of Tg and its relation to changes in food system. This review summarizes the understanding of concept of glass transition, its measurement, and application in food technology.