Phytase for Food Application Ursula Konietzny; Ralf Greiner
Food technology and biotechnology,
2006, Letnik:
44, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Phytase myo-inositol(1,2,3,4,5,6)hexakisphosphate phosphohydrolase, a phytate-specific phosphatase, is already used as a supplement in diets for monogastric animals to improvephosphate utilisation ...from phytatemyoinositol(1,2,3,4,5,6)hexakisphosphate, the major storage form of phosphate in plant seeds. In recent years, this class of enzymes has also been found increasingly interesting for use in processing and manufacturing of food for human consumption, particularly because the decline in food phytate results in an enhancement of mineral bioavailability. Different strategies could be applied to optimise phytate degradation during food processing and digestion in the human alimentary tract such as adjustment of more favourable conditions during food processing for the phytases naturally occurring in the raw material, addition of isolated phytases to the production process, use of raw material with a high intrinsic phytate-degrading activity either naturally present or introduced by genetic engineering and the use of recombinant food-grade microorganisms as carriers for phytate-degrading activity in the human gastrointestinal tract. Furthermore, phytases may find application in the production of functional foods or food supplements with health benefits. Last but not least, technological improvements are expected to occur due to phytate degradation during processing as shown for breadmaking, production of plant protein isolates, corn wet milling and the fractionation of cereal bran.
Ferulic acid (FA) and tocopherol (Toc) loaded solid lipid nanoparticles (SLN) were prepared by a hot homogenisation method. The particle size distribution, zeta potential and melting behaviour of the ...SLN as well as the stability, encapsulation efficiency and radical scavenging activity of FA and Toc in the SLN were analysed. The different formulations containing up to 2.8 mg g-1 of FA or Toc were stable during at least 15 weeks of storage at room temperature. Despite partial degradation and / or release of FA and Toc during storage, significant radical scavenging activity was maintained. DSC measurements and radical scavenging tests after different time periods revealed that the re-structuring of the lipid matrix was connected to the enhanced antioxidant activity of Toc but did not affect the activity of FA.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Minimally processed fresh-cut (MPFC) fruit products are an important source of functional ingredients, and increased consumers’ demand boosted an expansion of this segment of food industry. Apples ...(Malus sp.) are commonly cultivated fruits and processed to MPFC products. Their low shelf life is the main obstacle for gaining maximum nutritive and economic benefits. Enzymatic, metabolic, and other physiological processes induce changes that render the product spoiled and decrease the storage and marketability life of MPFC fruits. Such spoilage can be controlled by modified atmosphere packaging (MAP), but intrinsic influences of numerous MAP factors are not clearly elucidated. Microbial growth adds another layer of complexity to MAP. Mathematical modeling can successfully predict microbial growth and spoilage, hence saving production cost and provide better control over the production chain. In this sense, this review provides an overview of MAP’s factors that influence the quality of stored MPFC products. Focus was placed on apples and development of mathematical models that can be useful for prediction of their spoilage during storage and subsequently their shelf-life.
•Minimally processed fresh-cut (MPFC) fruits are an important food.•Apples (Malus domestica) are commonly processed to MPFC products.•Their short shelf-life is a main obstacle for gaining maximum processing benefits.•Review provides an overview of MAP’s factors that influence quality of MPFC products.•Focus was on spoilage and mathematical models useful for prediction of their spoilage.
The fermentation of vegetables is a traditional preservation method, that experiences a renaissance even in domestic households. Table salt is added to the fermentation batches to favor the growth of ...lactic acid bacteria usually. On an industrial scale, the fermentation brine is typically prepared with non-iodized table salt. In our study, we investigated the microbiota of cucumber fermentations using culture-dependent and -independent methods. We could show that the fermentation process of cucumbers and the involved microbiota is influenced by the concentration of table salt and not by the use of iodized table salt. Therefore, we conclude that the use of iodized table salt does not negatively affect the fermentation process. We could verify that iodine permeates the cucumbers by diffusion, leading to satisfactory iodine concentrations in the final food product. The industrial use of iodized table salt in food fermentations could contribute to maintain a constant iodine supply to the general public.
•The composition of the microbiota of fermented cucumbers depends on NaCl levels.•The microbiota and success of the fermentation are not influenced by iodization.•Use of iodized NaCl increases the iodine content of fermented cucumbers.
•Chitosan/TPP nanoparticles present potential to agriculture application.•Humic substances affected the dynamic equilibrium of the herbicide in the medium.•Humic substance influenced the toxicity of ...paraquat associated with the NPs.
Polymeric nanoparticles have been developed for several applications, among them as carrier system of pesticides. However, few studies have investigated the fate of these materials in the environment in relation to colloidal stability and toxicity. In nature, humic substances are the main agents responsible for complexation with metals and organic compounds, as well as responsible for the dynamics of these nanoparticles in aquatic and terrestrial environments. In this context, the evaluation of the influence of aquatic humic substances (AHS) on the colloidal stability and toxicity of polymeric nanoparticles of chitosan/tripolyphosphate with or without paraquat was performed. In this study, the nanoparticles were prepared by the ionic gelation method and characterized by size distribution measurements (DLS and NTA), zeta potential, infrared and fluorescence spectroscopy. Allium cepa genotoxicity studies and ecotoxicity assays with the alga Pseudokirchneriella subcapitata were used to investigate the effect of aquatic humic substances (AHS) on the toxicity of this delivery system. No changes were observed in the physical–chemical stability of the nanoparticles due to the presence of AHS using DLS and NTA techniques. However some evidence of interaction between the nanoparticles and AHS was observed by infrared and fluorescence spectroscopies. The ecotoxicity and genotoxicity assays showed that humic substances can decrease the toxic effects of nanoparticles containing paraquat. These results are interesting because they are important for understanding the interaction of these nanostructured carrier systems with species present in aquatic ecosystems such as humic substances, and in this way, opening new perspectives for studies on the dynamics of these carrier systems in the ecosystem.
Nanoparticles are ubiquitous in the environment. They originate from anthropogenic or natural sources or they are intentionally produced for different purposes. There exist manifold applications of ...nanoparticles in modern life leading unavoidably to a confrontation and interaction between nanomaterial and living organisms. Based on their wide distribution tending to increase steadily, the influence of particles based on silica and silver, exhibiting nominal sizes between 0.65 nm and 200 nm, on the physiology of the mycotoxigenic filamentous fungus Penicillium verrucosum was analyzed. The applied concentration and time-point, the size and the chemical composition of the particles was shown to have a strong influence on growth and mycotoxin biosynthesis. On microscopic scale it could be shown that silver nanoparticles attach to the mycelial surface. Moreover, silver nanoparticles with 0.65 nm and 5 nm in size were shown to internalize within the cell, form agglomerates in the cytoplasm and associate to cell organelles.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
Phytate‐degrading enzymes catalyse the step‐wise release of phosphate from phytate, the principle storage form of phosphorus in plant seeds and pollen. They are widespread in nature, ...occurring in plants and micro‐organisms, as well as in some animal tissues. Phytate‐degrading enzymes have been studied intensively in recent years because of the great interest in such enzymes for reducing phytate content in animal feed and food for human consumption. Phytate‐degrading enzymes are also of interest for producing defined breakdown products of phytate for kinetic and physiological studies. Certain myo‐inositol phosphates have been proposed to have novel metabolic effects and therefore, the physiological role of different myo‐inositol phosphates is presently undergoing extensive research. Generally, phytase behaves like a monomeric enzyme with molecular masses between 40 and 70 kDa. Up to now, two main types of phytate‐degrading enzymes have been identified; acid phytate‐degrading enzymes with an pH optimum around pH 5 and alkaline phytate‐degrading enzymes with an pH optimum around pH 8. Most of the so far described phytate‐degrading enzymes belong to the acidic type, and their optimal pH ranges from 4.5 to 6.0. This review summarises the molecular features as well as catalytic properties of phytate‐degrading enzymes and also discusses enzymatic phytate degradation.
The development of engineered nanometre sized materials (ENM) produced with food-grade ingredients and designed as delivery systems for organic and inorganic materials has gained increasing interest. ...The major reason for this trend is the aim to overcome problems associated with the low bioavailability of many bioactive compounds (BC) which are usually claimed to benefit human health. In this review, outcomes of studies investigating the potential bioavailability enhancement of BC using ENM as delivery systems are summarised and discussed. It focuses on
in vitro
and
in vivo
studies carried out with ENM produced with food-grade materials and designed for the delivery of vitamins, other secondary plant metabolites and minerals. Furthermore, the physical and physicochemical aspects governing the preparation of the systems, the loading of the BC, the stability of the delivery systems in food applications and finally the release of the BC in the gastrointestinal tract are also considered. The mechanisms leading to an enhanced bioavailability are based on (i) improved solubility of the BC under gastrointestinal conditions, (ii) the protection of the BC from the chemical conditions in the gastrointestinal tract (GIT), (iii) the controlled release within the GIT or (iv) an improved transfer through the intestinal wall. The main outcome of the review is that particle size, surface properties and physical state of the ENM are key parameters to be controlled aiming at an enhanced nutritional value of food materials. Furthermore, the bioavailability classification scheme (BCS) can help to understand the efficacy of different ENM for the delivery of specific BC.
This review focuses on how composition and structure of food-grade nanometre sized delivery systems affect the bioavailability of bioactive compounds.
Most Gram-negative phytopathogenic bacteria inject type III effector (T3E) proteins into plant cells to manipulate signaling pathways to the pathogen's benefit. In resistant plants, specialized ...immune receptors recognize single T3Es or their biochemical activities, thus halting pathogen ingress. However, molecular function and mode of recognition for most T3Es remains elusive. Here, we show that the Xanthomonas T3E XopH possesses phytase activity, i.e., dephosphorylates phytate (myo-inositol-hexakisphosphate, InsP
), the major phosphate storage compound in plants, which is also involved in pathogen defense. A combination of biochemical approaches, including a new NMR-based method to discriminate inositol polyphosphate enantiomers, identifies XopH as a naturally occurring 1-phytase that dephosphorylates InsP
at C1. Infection of Nicotiana benthamiana and pepper by Xanthomonas results in a XopH-dependent conversion of InsP
to InsP
1-phytase activity is required for XopH-mediated immunity of plants carrying the Bs7 resistance gene, and for induction of jasmonate- and ethylene-responsive genes in N. benthamiana.
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