کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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605325 | 880343 | 2013 | 11 صفحه PDF | دانلود رایگان |

Whey protein isolate (WPI) is a potential ingredient to manufacture shelf-stable transparent beverages if proteins are heat stable, i.e., without causing turbidity, precipitation and gelation after the required thermal processing to obtain commercial sterility (138 °C for 8 s or longer). However, information is lacking about stability of WPI during heating at 138 °C. Furthermore, novel technology and mechanistic understanding on how to produce clear products after heating systems with >5% WPI, particularly with salt, is needed. In this work, 5% w/v WPI was pretreated by microbial transglutaminase (mTGase) at three levels for 1–15 h at 50 °C, with and without prior preheating at 80 °C for 15 min. Heat stability of the pretreated samples at pH 7.0 and 0, 50, and 100 mM NaCl was evaluated at 138 °C. Samples pretreated by mTGase for a greater extent demonstrated improved heat stability. Samples subjected to sequential preheating and mTGase pretreatments produced clear dispersions even after heating at 138 °C for 30 min in the presence of 0 and 50 mM NaCl at pH 7. All pretreatments increased the magnitude of zeta-potential and resistance against thermal denaturation. The sequentially-pretreated WPI was the most heat-resistant, having decreased hydrodynamic diameter (<36 nm) during extended heating at 138 °C and 50 mM NaCl. The present study demonstrates the feasibility of using sequential preheating and mTGase pretreatments to develop sterilized beverage products with a high content (5% w/v) of whey protein and yet of transparent appearance at ambient temperatures.
Figure optionsDownload as PowerPoint slideHighlights
► Sequential preheating and mTGase pretreatments improved UHT stability of WPI.
► Hydrodynamic diameter (d4,3) increased after sequential pretreatments.
► Cross-linked proteins are resistant against aggregation during UHT.
► Cross-linked proteins are dissociated during UHT and restructured to bigger particles.
► Transparent dispersions corresponded to d4,3 smaller than 40 nm.
Journal: Food Hydrocolloids - Volume 31, Issue 2, June 2013, Pages 306–316