1,721,120 research outputs found
Design of pea protein isolate stabilized O/W/O double emulsions
No full textResearch interests on the alternative oil structuring techniques, like O/W/O double emulsions, oil foams and oil powders, for their applications in food processing have been increasingly significant due to their structural functionality and health benefits. Among them, O/W/O double emulsions have the most complex structure and are highly thermodynamic unstable. Thus, this study explores its destabilization mechanism from bulk to interface, and then some solutions were proposed and verified to improve the emulsion stability. To explore the stability mechanism, a model O/W/O double emulsion with standard surfactants, Tween 80 and PGPR, was constructed using a conventional two-step method. Results showed that unadsorbed Tween 80 in the intermediate water phase played a significant role in decreasing the interfacial moduli of the outer PGPR-assembled film by affecting the interfacial rearrangement. Additionally, the formed Tween 80 micelles could also transport inner oil molecules to further decrease the emulsion stability. As reported, proteins are biomacromolecules that can form an improved viscoelastic O-W interfacial film to improve the emulsion stability. However, natural pea protein isolate (PPI) has low solubility, limiting its emulsifying property and broad application. To overcome this issue, a novel and effective approach was presented for enhancing its techno-functional characteristics. After pH-shifting-ultrasound-heating (PUH) treatment, PPI solubility greatly improved from 29.5% to 90.4%. Furthermore, results demonstrated that the droplet size of the emulsion with PUH-treated PPI markedly reduced and its emulsion stability was significantly elevated. According to the above result, modified PPI, WPI and SC were further utilized to replace Tween 80 in the model O/W/O double emulsions. The release rates of the emulsions stabilized by proteins and PGPR were significantly reduced after 2 weeks of storage compared to Tween 80. Results showed that WPI and modified PPI could improve the interfacial moduli of both the inner and outer W-O films, further strengthening the mechanical properties of W-O interfaces against deformation and hence achieving the dual stabilization of O/W/O double emulsions. Considering the requirement of food processing, we proposed to structure the outer oil phase of O/W/O double emulsions with beeswax (BW) to meet the specific textural functionality while improving their stability against phase migration. As expected, all the BW-based emulsions kept excellent storage stability and similar crystallization and melting profiles. Interestingly, texture exhibited significant variations, with oleogelled emulsions possessing an improved firmness and OBC compared to W/O emulsions. This was probably caused by a larger fraction of the dispersed phase and higher wax concentration. Further, the stabilization mechanism was illustrated. BW could stabilize the oil-water interface as a Pickering particle, providing a physical barrier to improve the emulsion stability. Also, BW acted as the gelator of the bulk phase, forming the viscoelastic network to support the structural function of the emulsions. Additionally, the droplet-droplet interaction caused by the dispersed phase could promote the formation of the gelling network. In total, this research serves as a crucial guide for the design of stable O/W/O double emulsions
Exploring natural antifungal preservation strategies to extend bread shelf-life : from baking technology to biopreservation
No full textMould spoilage of bakery products is a serious problem resulting in a significant volume of food waste. Moreover, the food industry takes a keen interest in replacing chemical preservatives by natural alternatives in order to meet the consumers’ changing requirements as well as the clean label trend. This study focused on exploring natural water or oil soluble compounds with antifungal activity in bread and various baking technologies to reduce fungal growth of primarily Penicillium spp. and Aspergillus spp. The technologies considered included variations in par-baking conditions and the production of composite bread. The antimicrobial efficacy of antifungal compounds was assessed through in-vitro studies and predictive growth/no-growth models. The screening assays were macro-dilution (cf. agar dilution assays) and micro-dilution assays (cf. dilution assay in 96-well plates). Moreover, the effect of the undissociated acid fraction of weak organic acids such as those found in sourdough (e.g. acetic, lactic and phenyllactic acid), expressed in the aqueous phase of bread, became apparent. This provided additional information about the mode of action of the acids, enabling a better shelf-life prediction. Furthermore, the natural compounds were tested in actual dough and bread, assessing the technological quality of both dough and bread. In addition, the antifungal activity of the compounds was investigated by shelf-life and challenge tests. Throughout this work, it was shown that by adjusting the par-baking conditions, bread composition and packaging, it is possible to extend the shelf-life of par-baked bread in a natural way
Multiscale assessment of fat crystal networks in suspensions
No full textVetkristallisatie is uitermate belangrijk voor het gedrag en de functionaliteit van vetrijke voedingsproducten. Veel voedingsproducten zijn suspensies waarin deeltjes aanwezig zijn in een continue vetmatrix. Een dispergeermiddel wordt frequent gebruikt om de deeltjes in suspensie te houden. Dit proefschrift beoogt inzicht te geven in het vetkristalnetwerk onder invloed van toegevoegde deeltjes en dispergeermiddelen, op de nano-, meso- en microschaal. Hoofdstuk 1, de literatuurstudie, bespreekt het concept van vetkristallisatie, de hiërarchische structuur van het vetkristalnetwerk en de externe factoren die de vorming van vetkristalnetwerken beïnvloeden (isotherme temperatuur, afkoelsnelheid, afschuiving). Er wordt een overzicht gegeven van de meest voorkomende technieken en up-to-date mogelijkheden om het vetkristalnetwerk te bestuderen. Ten slotte worden het effect van de aanwezigheid van deeltjes en de toevoeging van een dispergeermiddel besproken als introductie tot vetkristallisatie in suspensies. In dit hoofdstuk wordt het belang van het huidige onderzoek gekaderd. Hoofdstuk 2 en 3 richten zich op de belangrijkste analysetechnieken om vetkristallisatie te bestuderen. In Hoofdstuk 2 worden de mogelijkheden met betrekking tot X-stralen analyse onderzocht. X-stralen analyse onder grote, kleine en ultrakleine hoeken wordt toegepast om de statische kristallisatie van palmolie als referentiesysteem te bestuderen. Hoofdstuk 3 ontrafelt de meso- en microschaal van het vetkristalnetwerk door verschillende microscopietechnieken toe te passen. Binnen dit proefschrift werden sucrose-esters gebruikt als dispergeermiddel. Hoofdstuk 4 bespreekt kort de zelfassemblage en thermische eigenschappen van zes verschillende sucrose-esters. Hun chemische samenstelling, d.w.z. het type vetzuurketen en de graad van sucrosesubstitutie, houdt verband met hun kristalvorming en smeltpunt. In Hoofdstuk 5 wordt het effect van sucrose-esters op de statische kristallisatie van palmolie bestudeerd. De nano-, meso- en microschaal worden bestreken door toepassing van thermische analyse, X-stralen analyse en microscopie. Om het effect van de vetsamenstelling op de kristallisatie te bestuderen, werden ook melkvet (AMF) en gehydrogeneerde palmpitstearine (HPKS) onderzocht. Hoofdstuk 6 bespreekt het effect van de vetzuursamenstelling, de triglyceridensamenstelling en het resulterende vast vetgehalte op de kristallisatie en de toepasbaarheid van geselecteerde analysetechnieken uit Hoofdstuk 2 en 3. Daarnaast wordt het effect op de vetkristallisatie besproken wanneer sucrose-esters worden toegevoegd aan de verschillende vetten. Hoofdstuk 7, 8 en 9 omvatten de kristallisatie van suspensies. In Hoofdstuk 7 worden eerst de deeltjes, sucrose, inuline en natriumcaseïnaat gekarakteriseerd en vervolgens worden de deeltjesconcentratie van de suspensies en de toevoeging van sucrose-ester kort besproken. Hoofdstuk 8 behandelt de statische kristallisatie van suspensies, en bespreekt het effect van deeltjestoevoeging en het gecombineerde effect daarvan met de toevoeging van sucrose-esters. In Hoofdstuk 9 wordt dynamische kristallisatie bestudeerd door het effect van hoge en lage afschuifsnelheden op de ontwikkeling van vetkristalnetwerken op nano- tot microschaal te bestuderen
Lactiplantibacillus plantarum FS4722 with function of attenuating hyperuricemia : its isolation, potential mechanism and application in lipid-based delivery system
No full textHyperuricemia (HUA), characterized by high serum urate concentrations exceeding the saturation threshold of 6.8 mg/dl, has become one of the major public health issues which receives considerable attention. Probiotics have been recognized as pivotal players in attenuating HUA. Extensive studies have revealed that the health benefits attributed to probiotics are highly strain-specific, suggesting that different strains of probiotics could employ distinct mechanisms to combat HUA. Therefore, the identification on probiotic strain and its strain-specific mechanism targeting HUA should be clarified.
This study aims to identify a specific probiotic candidate with potential function of anti-hyperuricemia from Chinese fermented vegetables. The role and underlying mechanisms of the identified probiotic in regulating serum urate levels in vivo was investigated in HUA mice. After that, oleogel was fabricated as delivery system to protect the probiotic from adverse factors during the gastrointestinal digestion, which further facilitates its function exerting in host
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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