Species of Cronobacter – A review of recent advances in the genus and their significance in infant formula milk

Enterobacter sakazakii has recently been reclassified as the novel genus Cronobacter. These bacteria have been associated with disease outbreaks and sporadic infections, particularly in premature and immunocompromised infants. Cronobacter spp. can cause foodborne infections such as neonatal meningitis, septicaemia and necrotising enterocolitis. Infant formula milk is the only food source that has been epidemiologically linked to disease outbreaks caused by Cronobacter spp. This holds particular risk for premature and immunocompromised infants. This review focuses on the recent reclassification of Cronobacter and the importance that these pathogens pose to the food industry. The inactivation, inhibition, thermal, osmotic and desiccation tolerances of these bacteria are described, as well as improvements made in the isolation and detection methods of members of Cronobacter from food products.     

Towards improving the nutrition and health of the aged: the role of sprouted grains and encapsulation of bioactive compounds in functional bread – a review

Aging reduces the absorption of nutrients. Literature related to functional bread processing techniques including sprouting of grains and the application of encapsulation technology and the bioavailability of bioactives was reviewed. Functional ingredients including sprouted/germinated grain particularly brown rice and wheat flours enhance the bioactive properties of functional bread. Ingredients with high polyphenol content such as lavender and melissa by-products, tea-extracts and aronia powder enhance the bioactive content and appear to have a favourable effect on the shelf-life of bread and antioxidant status of consumers. Incorporation of encapsulated bioactive compounds into bread have a huge potential to improve the bread quality and increase the bioavailability and bioaccessibility of bioactive compounds including polyphenols. More investigations and new areas of research should focus on sprouted grain flours and the application of encapsulation technologies especially nanoencapsulation to optimize the bioactivity, storage, bioavailability and nutritional profile of bread to improve nutrition and health with aging.     

Carbon nanotube and its applications in textile industry – A review

One of the major components of nanotechnology is Carbon nanotube (CNT) that can have a length-to-diameter ratio more than 1,000,000. They are used in several fields in material science, due to their exceptional electrical, mechanical, and thermal properties, which are anisotropic. Different techniques have been developed to produce CNT. They have good potential for applications in various technological areas such as nanoelectronic, biotechnology, material science, polymer, composite, and textile industries. In this paper, recent researches on application of CNT in textile industry are reviewed. Treatment of textiles with CNT leads to the production of a wide variety of conductive textiles with different electrical properties. The wear performances of fabrics apply with CNT to open the potentiality of producing composite materials for conventional and innovative applications, ranging from conventional apparel and sportswear to protective clothing, heating equipment, automotive textiles, building covering, geo-textiles, biomedical textiles, etc.     

Gelation of gellan – A review

Gellan is an anionic extracellular bacterial polysaccharide discovered in 1978. Acyl groups present in the native polymer are removed by alkaline hydrolysis in normal commercial production, giving the charged tetrasaccharide repeating sequence: → 3)-β-d-Glcp-(1 → 4)-β-d-GlcpA-(1 → 4)-β-d-Glcp-(1 → 4)-α-l-Rhap-(1 →. Deacylated gellan converts on cooling from disordered coils to 3-fold double helices. The coil–helix transition temperature (T_m) is raised by salt in the way expected from polyelectrolyte theory: equivalent molar concentrations of different monovalent cations (Group I and Me₄N⁺) cause the same increase in T_m; there is also no selectivity between different divalent (Group II) cations, but divalent cations cause greater elevation of T_m than monovalent. Cations present as counterions to the charged groups of the polymer have the same effect as those introduced by addition of salt. Increasing polymer concentration raises T_m because of the consequent increase in concentration of the counterions, but the concentration of polymer chains themselves does not affect T_m. Gelation occurs by aggregation of double helices. Aggregation stabilises the helices to temperatures higher than those at which they form on cooling, giving thermal hysteresis between gelation and melting. Melting of aggregated and non-aggregated helices can be seen as separate thermal and rheological processes. Reduction in pH promotes aggregation and gelation by decreasing the negative charge on the polymer and thus decreasing electrostatic repulsion between the helices. Group I cations decrease repulsion by binding to the helices in specific coordination sites around the carboxylate groups of the polymer. Strength of binding increases with increasing ionic size (Li⁺ < Na⁺ < K⁺ < Rb⁺ < Cs⁺); the extent of aggregation and effectiveness in promoting gel formation increase in the same order. Me₄N⁺ cations, which cannot form coordination complexes, act solely by non-specific screening of electrostatic repulsion, and give gels only at very high concentration (above ∼0.6 M). At low concentrations of monovalent cations, ordered gellan behaves like a normal polymer solution; as salt concentration is increased there is then a region where fluid “weak gels” are formed, before the cation concentration becomes sufficient to give true, self-supporting gels. Aggregation and consequent gelation with Group II cations occurs by direct site-binding of the divalent ions between gellan double helices. High concentrations of salt or acid cause excessive aggregation, with consequent reduction in gel strength. Maximum strength with divalent cations comes at about stoichiometric equivalence to the gellan carboxylate groups. Much higher concentrations of monovalent cations are required to attain maximum gel strength. The content of divalent cations in commercial gellan is normally sufficient to give cohesive gels at polymer concentrations down to ∼0.15 wt %. Gellan gels are very brittle, and have excellent flavour release. The networks are dynamic: gellan gels release polymer chains when immersed in water and show substantial recovery from mechanical disruption or expulsion of water by slow compression. High concentrations of sugar (∼70 wt % and above) inhibit aggregation and give sparingly-crosslinked networks which vitrify on cooling. Gellan forms coupled networks with konjac glucomannan and tamarind xyloglucan, phase-separated networks with kappa carrageenan and calcium alginate, interpenetrating networks with agarose and gelling maltodextrin, and complex coacervates with gelatin under acidic conditions. Native gellan carries acetyl and l-glyceryl groups at, respectively, O(6) and O(2) of the 3-linked glucose residue in the tetrasaccharide repeat unit. The presence of these substituents does not change the overall double helix structure, but has profound effects on gelation. l-Glyceryl groups stabilise the double helix by forming additional hydrogen bonds within and between the two strands, giving higher gelation temperatures, but abolish the binding site for metal ions by changing the orientation of the adjacent glucuronate residue and its carboxyl group. The consequent loss of cation-mediated aggregation reduces gel strength and brittleness, and eliminates thermal hysteresis. Aggregation is further inhibited by acetyl groups located on the periphery of the double helix. Gellan with a high content of residual acyl groups is available commercially as “high acyl gellan”. Mixtures of high acyl and deacylated gellan form interpenetrating networks, with no double helices incorporating strands of both types. Gellan has numerous existing and potential practical applications in food, cosmetics, toiletries, pharmaceuticals and microbiology.     

Functional food ingredients for the management of obesity and associated co-morbidities – A review

Worldwide obesity has reached a pandemic proportion. World Health Organization (WHO) estimates that by 2020, two thirds of the global disease burden will be attributable to obesity and obesity associated complications. Existing anti-obesity drugs, affecting one of the fundamental processes of the weight regulation in human body, have displayed serious side effects which outweigh their beneficial effects. Clinical and non-clinical researchers in this area are now facing a challenge to search for non-pharmacological alternatives for the prevention of obesity. Dietary interventions and life style changes with enhanced physical activity are two such options. Considering the importance of dietary interventions, the present review highlights the role, significance and potential of functional food ingredients for the management of obesity and associated co-morbidities.     

Olive oil flavoured by the essential oils of Mentha × piperita and Thymus mastichina L.

The present study reports the development of flavoured olive oils by the incorporation of Mentha × piperita L. and Thymus mastichina subsp. mastichina essential oils. This M. × piperita L. is an unusual cultivar characterized by a high content of linalyl acetate (72.0%) and linalool (12.3%). T. mastichina is a 1,8-cineole chemotype (64.1%). Preliminary sensory tests were carried out to establish the lower levels and the upper levels of the essential oils incorporation. Response surface methodology (RSM) was used to access a convenient ratio of T. mastichina and M. × piperita essential oils. According to RSM results three mixtures located in regions that produced higher sensory scores to aromatic plant aroma, cooling and pungency were selected and subjected to a consumer test. Results indicated that high levels of Thymus essential oil (0.008 mg/kg) were those ranked the best but Mentha essential oil incorporation must be kept at low levels (0.002 mg/kg).     

Processing of high-protein yoghurt – A review

High-protein yoghurt has gained increased consumer interest over the recent years, partly driven by improvements in taste and texture; there is also greater scientific evidence on dairy protein health benefits. The protein content of yoghurt can be increased prior to fermentation by addition of dairy powder, evaporation or membrane filtration, or after fermentation by straining, mechanical separation, or membrane filtration. Concentration of yoghurt after fermentation produces large volumes of acid whey, a major concern for the dairy industry; by concentrating prior to fermentation, production of acid whey is avoided. Different processing techniques influence yoghurt composition, structure, rheology, and sensory properties. This review discusses the challenges, opportunities, the influence of macro components in milk and different processing techniques on composition, structure, rheology, and sensory properties of high-protein yoghurt, along with their benefits and drawbacks for the dairy producer.     

Application and Optimization of Microwave-Assisted Extraction and Dispersive Liquid–Liquid Microextraction Followed by High-Performance Liquid Chromatography for the Determination of Oleuropein and Hydroxytyrosol in Olive Pomace

In the present study, a new method based on microwave-assisted extraction and dispersive liquid–liquid microextraction (MAE–DLLME) followed by high-performance liquid chromatography (HPLC) was proposed for the separation and determination of oleuropein (Ole) and hydroxytyrosol (HyT) from olive pomace samples. The effective factors in the MAE–DLLME process such as microwave power, extraction time, the type and volume of extraction, and dispersive solvents were studied and optimized with the aid of response surface methodology (RSM) based on a central composite design (CCD) to obtain the best condition for Ole and HyT extraction. At the optimized conditions, parameter values were 220 W microwave power, 12 min extraction time, 60 μL extracting solvent, and 500 μL dispersive solvent. The calibration graphs of the proposed method were linear in the range of 10–500,000 μg L^?1, with the coefficient of determination (R²) higher than 0.99 for Ole and HyT. Repeatability of the method, described as the relative standard deviation (RSD), was 4.12–5.63% (n?=?6). The limits of detection were 35 and 20 μg L^?1 for Ole and HyT, respectively. The recoveries of these compounds in the spiked olive pomace sample were from 93 to 98%. The proposed method, MAE–DLLME–HPLC–UV, was an accurate, rapid, and reliable method when compared with previous methods.     

Ultrahigh pressure extraction of bioactive compounds from plants—A review

Extraction of bioactive compounds from plants is one of the most important research areas for pharmaceutical and food industries. Conventional extraction techniques are usually associated with longer extraction times, lower yields, more organic solvent consumption, and poor extraction efficiency. A novel extraction technique, ultrahigh pressure extraction, has been developed for the extraction of bioactive compounds from plants, in order to shorten the extraction time, decrease the solvent consumption, increase the extraction yields, and enhance the quality of extracts. The mild processing temperature of ultrahigh pressure extraction may lead to an enhanced extraction of thermolabile bioactive ingredients. A critical review is conducted to introduce the different aspects of ultrahigh pressure extraction of plants bioactive compounds, including principles and mechanisms, the important parameters influencing its performance, comparison of ultrahigh pressure extraction with other extraction techniques, advantages, and disadvantages. The future opportunities of ultrahigh pressure extraction are also discussed.     

Ecology of Vastedda della valle del Belìce cheeses: A review and recent findings to stabilize the traditional production

The increasing request for classic foods has led to a higher demand for cheeses enjoying a “recognition of quality” status. This phenomenon has also affected Sicilian dairy products, in particular protected designation of origin (PDO) “Vastedda della valle del Belìce” (VdB), a cheese traditionally available only during the summer season, but requested year round. The variations of the microbial populations of raw milk among the seasons influence the microbiological quality of the cheeses produced. This review article reports the historical importance of cheeses and the traditional equipment used for dairy productions in Sicily with a specific focus on VdB. The microbial ecology of this cheese is thoroughly discussed. The recent findings to stabilize the traditional VdB production protocol with regards to the microbial composition and the organoleptic characteristics of the final cheeses are reviewed. The selection of starter lactic acid bacteria from PDO cheeses, their in vitro and in vivo application, and, overall, the setup of their inoculation, have all generated a novel production protocol. The innovation was respectful of the traditional discipline, essentially based on the ad hoc biofilm formation on the traditional wooden equipment, and allowed the preservation of VdB typicality. Future prospects are summarized.     

The use of exergetic indicators in the food industry – A review

Assessment of sustainability will become more relevant for the food industry in the years to come. Analysis based on exergy, including the use of exergetic indicators and Grassmann diagrams, is a useful tool for the quantitative and qualitative assessment of the efficiency of industrial food chains. In this paper, we review the methodology of exergy analysis and the exergetic indicators that are most appropriate for use in the food industry. The challenges of applying exergy analysis in industrial food chains and the specific features of food processes are also discussed.     

Bacillus thermoamylovorans – A new threat to the dairy industry – A review

Bacillus thermoamylovorans is a newly described spore forming bacterium emerging in the dairy industry. There is an increasing threat of B. thermoamylovorans contamination, not only in food ingredients and raw milk, but also in sterilised milk and dairy products. Animal feed, processing equipment, and farm environments are potential entry points for contamination of milk with B. thermoamylovorans. The ability of B. thermoamylovorans to produce lipolytic and β-galactosidase enzymes is linked to food spoilage. B. thermoamylovorans spores have a heat resistance comparable with that of the spores of Bacillus sporothermodurans, indicating the potential to survive ultra-high temperature treatments. However, despite the rise in reports of the isolation of B. thermoamylovorans from dairy samples, there have been few reports on the characterisation of these bacteria. The origin, characteristics and potential issues resulting from B. thermoamylovorans in the dairy industry and potential methods of control are discussed in this review.     

α-Glucosidase and α-amylase inhibitors from seed oil: A review of liposoluble substance to treat diabetes

One of the effective managements of diabetes mellitus, in particular, noninsulin-dependent diabetes mellitus, is to retard the absorption of glucose by inhibition of carbohydrate hydrolyzing enzymes, such as α-glucosidase and α-amylase, in the digestive organs. Currently, there is renewed interest in plant-based medicines and functional foods modulating physiological effects in the inhibition of α-glucosidase and α-amylase. Accordingly, inhibitors of α-glucosidase or α-amylase derived from various sources have also been isolated, and majority of phenolic compounds and their effects have been investigated in animals as well. As such, when the presence of α-glucosidase inhibitor in many foodstuffs was screened for, we found that vegetable seed oil also strongly inhibited α-glucosidase and α-amylase. Seed oil is an important source of liposoluble constituents with potential for inhibition of these enzymes, hence can also be used as therapeutic or functional food sources. Therefore, this review is aimed at highlighting the main liposoluble classes of α-glucosidase and α-amylase inhibitors, but it is not intended to be an exhaustive review on the subject.     

Discrete choice experiments in the analysis of consumers’ preferences for finfish products: A systematic literature review

Discrete choice experiments (DCEs) have become an important tool for assessing the preferences of consumers for finfish seafood products. This investigation presents a systematic literature review of studies performed in the last 20 years (2000–2019) that use DCEs to analyse consumers’ preferences for finfish products, with the purpose to identify the main insights of consumer behaviour towards these products, the most used attributes for this type of experiments and to discuss and compare some willingness to pay estimations. We found that origin was the most used attribute for this kind of experiments, while other important factors were the harvest method, a specific certification label and the species or products considered. The WTP estimates evidenced that consumers are willing to pay premiums for domestic products, while similarly, wild products were preferred over farmed products. Also, there were higher WTP estimates for certified products, in which specific certification labels were better options rather than just claiming that the product was certified or not. All claims and labels related to sustainability, nutritional, health and safety information provided premiums that consumers were willing to pay, however, the importance differed depending on the type of label or claim, the country and species. Future research should consider the influence of being or not the main purchaser in the household, as it might affect the WTP values. Also, given the importance, future research extensions using DCEs are needed on the Chinese and Asian finfish market.     

Invited review: The role of the blood–milk barrier and its manipulation for the efficacy of the mammary immune response and milk production

The intact blood–milk barrier (BMB) prevents an uncontrolled exchange of soluble and cellular components between blood and milk in the mammary gland. It enables the sustainability of the optimal milk composition for the nourishment of the offspring. Endothelial cells, connective tissue, the basal membrane, and mainly the epithelial cells provide the semipermeability of this barrier, allowing only a selective transfer of components necessary for milk production. The epithelial cells are closely connected to each other by different formations, in which the tight junctions are the most critical for separating the milk-containing compartments from the surrounding extracellular fluid and vasculature. During mastitis, the integrity of the BMB is reduced. This facilitates the transfer of immune cells and immune factors such as antibodies from blood into milk. Simultaneously, the transfer of soluble blood constituents without an obvious immune function into milk is promoted. Furthermore, a reduced BMB integrity causes a loss of milk constituents into the blood circulation. Different mechanisms are responsible for the barrier impairment including tight junction opening, but also cell degradation. To promote the cure of mastitis, the targeted manipulation of the BMB permeability may be a tool to optimize the immune function of the mammary gland. An intensified opening of the BMB supports the antibody transfer from blood into milk, which is supposed to increase the contribution of the specific immune system in the immune defense. On the contrary, a fast closure of the BMB during the recovery from mastitis can accelerate the normalization of milk composition and milk yield. Various agents have been experimentally shown to either open (e.g., pathogens and pathogen-associated molecular patterns, several nonsteroidal anti-inflammatory drugs, oxytocin, calcium chelators) or close (e.g., glucocorticoids, nonsteroidal anti-inflammatory drugs, natural anti-inflammatory drugs) the BMB.     

Omega-3 fatty acids – A review of existing and innovative delivery methods

Omega-3 fatty acids are generally under-consumed in Western diets; a factor that may largely be attributed to low intake of oily fish. Although supplementation strategies offer one approach in terms of improving blood fatty acid levels, rates of compliance are generally low due to difficulties in swallowing capsules, or unfavorable aftertastes. Consequently, new approaches, including food-based strategies, may be an alternative approach to improving omega-3 status and the health of public sectors. This paper sets out to discuss and review how the use of novel food vehicle and delivery advancements may be used to improve omega-3 status, which may have wider benefits for public health and well-being.