Food Engineering / Gıda Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/12

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Author: search.filters.author.Harsa, ŞebnemSubject: search.filters.subject.Whey

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  • Article
    Citation - WoS: 15
    Citation - Scopus: 19
    Whey Protein-Pullulan (wp/Pullulan) Polymer Blend for Preservation of Viability of Lactobacillus Acidophilus
    (Taylor and Francis Ltd., 2015) Çabuk, Burcu; Harsa, Hayriye Şebnem; Harsa, Şebnem
    In this study, whey protein isolate-pullulan (WP/pullulan) microspheres were developed to entrap the probiotic Lactobacillus acidophilus NRRL-B 4495 by spray-drying technique. Microcapsules were analyzed for physicochemical characteristics including morphology, particle size, moisture content, water activity, dissolution time, and color properties. Results revealed that microcapsules were spherical in shape and obtained particle sizes between 5 and 160 µm, with an average size of around 50 µm. Blending pullulan with WP provided enhanced survival of probiotic bacteria during spray drying with a final viable cell number of 8.81 log CFU/g of microcapsule. Encapsulated probiotics were also found to have significantly (p ≤ 0.05) higher survived cell numbers compared to free probiotics under detrimental gastrointestinal conditions. Moreover, dissolution analysis suggested that protein-polysaccharide powdered microcapsules showed pH-sensitive dissolution properties in simulated gastric juice and simulated intestinal juice.
  • Article
    Citation - WoS: 13
    Citation - Scopus: 14
    Nanotubular Structures Developed From Whey-Based ?-Lactalbumin Fractions for Food Applications
    (John Wiley and Sons Inc., 2014) Tarhan, Özgür; Harsa, Şebnem
    Whey proteins have high nutritional value providing use in dietary purposes and improvement of technological properties in processed foods. Functionality of the whey-based α-lactalbumin (α-La) may be increased when assembled in the form of nanotubes, promising novel potential applications subject to investigation. The purpose of this study was to extract highly pure α-La from whey protein isolate (WPI) and whey powder (WP) and to construct protein nanotubes from them for industrial applications. For protein fractionation, WPI was directly fed to chromatography, however, WP was first subjected to membrane filtration and the retentate fraction, whey protein concentrate (WPC), was obtained and then used for chromatographic separation. α-La and, additionally β-Lg, were purified at the same batches with the purities in the range of 95%-99%. After enzymatic hydrolysis, WPI-based α-La produced chain-like and long nanotubules with ∼20 nm width while WPC-based α-La produced thinner, miscellaneous, and fibril-like nanostructures by self-assembly. Raman and FT-IR spectroscopies revealed that α-La fractions, obtained from both sources and the nanostructures, developed using both fractions have some structural differences due to conformation of secondary structure elements. Nanotube formation induced gelation and nanotubular gel network entrapped a colorant uniformly with a transparent appearance. Dairy-based α-La protein nanotubules could be served as alternative gelling agents and the carriers of natural colorants in various food processes.