Acid-producing activitiy of lyophilized lactic streptococcal cheese starter concentrates Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/x920g157h

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • Freeze-dried concentrates (DRICONS) of lactic streptococcal starter bacteria (single and mixed strains) were prepared in different lyophilization media and stored under vacuum and several gases. DRICONS were tested for survival and acid-producing activity after storage for up to a year by rehydration with water to the original pre-lyophilization volume. Acid production was measured during incubation at 30 C for up to 6 h and 22 C for up to 18 h. Lyophilization media evaluated included 11% nonfat milk, nonfat milk containing 10% maltose, and sucrose-peptone (10%-5%) solution. Storage conditions evaluated included vacuum-sealing and storage under atmospheres of air, argon, carbon dioxide and nitrogen. Best results were achieved with commercial mixed strain starter cultures of unknown strain composition which were purchased as direct vat set Cheddar cheese starters. DRICONS of these cultures were active and stable at ambient temperatures (25 C) for several months when vacuum-sealed and stored in amber containers filled with argon and when lyophilized in 11% nonfat milk containing 15% sodium glycerophosphate. For example, DRICONS of 10 such cultures when stored for 5 to 8 months at 25 C produced an average percent titratable acidity of 0.97 (range 0.86 to 1.03) at 22 C in 18 h when rehydrated to the original prelyophilization volume in water and 1% inoculum was made into steamed (95 C for 40 min) nonfat milk; when incubated at 30 C for 6 h, the average was 0.60% (range 0.35 to 0.80%) for DRICONS stored 3 to 4 months. The apparent enhanced acid production by rehydrated DRICONS incubated at 22 C as compared to 30 C suggests that such preparations may have greater application for direct inoculation of bulk starter milk than for cheese vat milk.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome) using Capture Perfect 3.0 on a Canon DR-9050C in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Submitted by Sergio Trujillo (jstscanner@gmail.com) on 2013-09-18T19:06:40Z No. of bitstreams: 1 YangNiannLuu1980.pdf: 620720 bytes, checksum: a96e373731eb0177d66ad290b315361b (MD5)
  • description.provenance : Made available in DSpace on 2013-09-25T21:47:25Z (GMT). No. of bitstreams: 1 YangNiannLuu1980.pdf: 620720 bytes, checksum: a96e373731eb0177d66ad290b315361b (MD5) Previous issue date: 1979-04-26
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2013-09-18T19:16:51Z (GMT) No. of bitstreams: 1 YangNiannLuu1980.pdf: 620720 bytes, checksum: a96e373731eb0177d66ad290b315361b (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2013-09-25T21:47:25Z (GMT) No. of bitstreams: 1 YangNiannLuu1980.pdf: 620720 bytes, checksum: a96e373731eb0177d66ad290b315361b (MD5)

Relationships

Parents:

This work has no parents.

Last modified

Downloadable Content

Download PDF

Items