CS1_soy_sauce-AK - Case Study ISoy Sauce. Scenario: Brewing...

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Case Study I—Soy Sauce. Scenario: Brewing soy sauce is one of the original biotech industries. Soy sauce was shipped in barrels within Asia over 500 years ago, and in bottles to Europe by the 1600s. Now soy sauce is used all over the world. About 5000 years ago in China, people grew soybean crops for food and animal feed. Because soybeans spoil easily, salt was added as a preservative. Over time the beans fermented much like pickles or sauerkraut. Unlike pickles, however the soy beans turn into a paste called miso as they ferment. The paste is easier to digest than the unfermented soy beans, and people have been eating it for centuries. About 500 years ago, someone discovered that instead of discarding the sauce at the bottom of the barrels, theycould use it for cooking. Thus, soy sauce was invented. Unlike making wine from grapes, soy sauce brewing is performed in two stages. First, the soy beans are steamed and mixed with toasted crushed wheat. Fungi Aspergillus oryzae and Aspergillus sojae are added to the mixture to make koji (the first step in the soy sauce-making process) that is then left uncovered for a couple of days. Next, salt and water are added to koji to form a mash called moromi . Moromi is then put in airtight containers where it is allowed to ferment for at least 6 months. The mash is then squeezed to get the liquid soy sauce. Finally, the sauce is filtered, pasteurized, and tightly bottled for distribution. Questions I. Koji phase 1. In the koji phase, the mixture is inoculated with two species of Aspergillus fungi, and the mixture is left uncovered. i) If you analyze the microbial populations found in koji, what do you expect to find? A. Aspergillus fungi only B. Aspergillus and other fungi C. bacteria only D. various fungi (including Aspergillus) and bacteria E. no microbes ii) If you expect to find microbes other than the ones with which the mixture was inoculated, explain where they come from and why they thrive in koji. If you do not expect to find additional populations, explain why not.
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This note was uploaded on 11/02/2008 for the course BILD 1 taught by Professor Unk during the Spring '08 term at UCSB.

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CS1_soy_sauce-AK - Case Study ISoy Sauce. Scenario: Brewing...

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