HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Interpretive Summary Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hassan, A. N. Articles by Awad, S. Search for Related Content PubMed PubMed Citation Articles by Hassan, A. N. Articles by Awad, S.

Application of Exopolysaccharide-Producing Cultures in Reduced-Fat Cheddar Cheese: Cryo-Scanning Electron Microscopy Observations^*

A. N. Hassan and S. Awad

Minnesota-South Dakota Dairy Foods Research Center, Dairy Science Department, South Dakota State University, Brookings 57007

Corresponding author: Ashraf N. Hassan; e-mail: Ashraf.Hassan{at}sdstate.edu.

The microstructure of reduced- and full-fat Cheddar cheeses made with exopolysaccharide (EPS)-producing and nonproducing cultures was observed using cryo-scanning electron microscopy. Fully hydrated cheese samples were rapidly frozen in liquid nitrogen slush (–207°C) and observed in their frozen hydrated state without the need for fat extraction. Different EPS-producing cultures were used in making reduced-fat Cheddar cheese. Full-fat cheese was made with a commercial EPS-nonproducing starter culture. The cryo-scanning electron micrographs showed that fat globules in the fully hydrated cheese were surrounded by cavities. Serum channels and pores in the protein network were clearly observed. Young (1-wk-old) full-fat cheese contained wide and long fat serum channels, which were formed because of fat coalescence. Such channels were not observed in the reduced-fat cheese. Young reduced-fat cheese made with EPS-nonproducing cultures contained fewer and larger pores than did reduced-fat cheese made with a ropy strain of Lactococcus lactis ssp. cremoris (JFR1), which had higher moisture levels. A 3-dimensional network of EPS was observed in large pores in cheese made with JFR1. Major changes in the size and distribution of pores within the structure of the protein network were observed in all reduced-fat cheeses, except that made with JFR1, as they aged. Changes in porosity were less pronounced in both the full-fat and the reduced-fat cheeses made with JFR1.

Key Words: Cheddar • exopolysaccharides • cryo-scanning electron microscopy • microstructure

Abbreviation key: EPS = exopolysaccharide, FFC = full-fat control cheese, RF-JFR1 = reduced-fat cheese made with the ropy culture Lactococcus lactis ssp. cremoris JFR1, SEM = scanning electron microscopy

This article has been cited by other articles:

				A. N. Hassan ADSA Foundation Scholar Award: Possibilities and Challenges of Exopolysaccharide-Producing Lactic Cultures in Dairy Foods J Dairy Sci, April 1, 2008; 91(4): 1282 - 1298. [Abstract] [Full Text] [PDF]

				A. N. Hassan, S. Awad, and V. V. Mistry Reduced Fat Process Cheese Made from Young Reduced Fat Cheddar Cheese Manufactured with Exopolysaccharide-Producing Cultures J Dairy Sci, August 1, 2007; 90(8): 3604 - 3612. [Abstract] [Full Text] [PDF]

				S. Awad, A. N. Hassan, and K. Muthukumarappan Application of Exopolysaccharide-Producing Cultures in Reduced-Fat Cheddar Cheese: Texture and Melting Properties J Dairy Sci, December 1, 2005; 88(12): 4204 - 4213. [Abstract] [Full Text] [PDF]

				A. N. Hassan, S. Awad, and K. Muthukumarappan Effects of Exopolysaccharide-Producing Cultures on the Viscoelastic Properties of Reduced-Fat Cheddar Cheese J Dairy Sci, December 1, 2005; 88(12): 4221 - 4227. [Abstract] [Full Text] [PDF]