Evelyn Watts

Louisiana is one of the biggest hot sauce producers in the U.S. with more than 35 different brands available in the market. Hot pepper sauce is made from red hot peppers and used for cooking and seasoning because of its unique pungent flavor. The most popular pepper species used for hot sauce production is tabasco peppers; however, habanero, jalapeno, cayenne and other bell chilies are also popular among processors. Hot sauce in Louisiana is mainly produced in the New Iberia, St. Martinville and Lafayette areas.

Louisiana hot sauces are manufactured using slightly different processes. In general, their production requires the fermentation of a hot red chili pepper mash in wooden or plastic barrels for a period between two weeks and three years. The exact procedure to produce hot sauce varies among companies and is considered a guarded trade secret. The main differences among products are the amount of salt added, the fermentation time, the degree of grinding and the percentage of added vinegar.

In the fermentation of most food products, the prevailing microbial groups are lactic acid bacteria and yeast, the relative population of which defines the characteristics of the final product. Lactic acid bacteria are widely distributed in nature and are typically involved in various food fermentation processes.

Consumers often base their overall impression and choice of food on flavor and aroma. There are more than 125 volatile compounds identified in fresh and processed red hot chili peppers. A volatile compounds evaluation determines if the fermentation process has been achieved in producing the desired final product. Changes in volatile compounds of chili peppers take place during ripening stages and fermentation.

LSU AgCenter scientists have conducted research to help the hot sauce industry understand the fermentation process of pepper mash. The purpose of this study was to identify the main microorganisms involved in pepper fermentation and its impact in acidity, flavor, aroma and color. During a 550-day period, pepper mash was fermented, mimicking natural conditions. The mash was sampled to analyze microbiological and physical and chemical changes.

The research team found that red hot chili pepper mash fermentation occurred in four stages where a symbiosis between lactic acid bacteria and yeast makes possible the fermentation of the mash. Subsequently, the fermentation process intensifies volatile compounds important for the quality of aroma and flavor of hot sauce. The primary lactic acid bacteria identified during the different stages of pepper mash fermentation were Lactobacillus plantarum and Lactococcus spp. The primary yeast involved was Candida spp. These lactic acid bacteria and yeast have also been identified in other fermented products and are related to the production of aroma-causing compounds.

During the fermentation, an increase in acidity and slight changes in color in the mash were observed (Figure 1). Changes in concentration of volatile compounds were observed, which affected characteristic flavors and aromas in the production of hot sauce (Figure 2). Six main volatile compounds were identified during this study (Table 1). At the end of the fermentation process, a reduction of lactic acid bacteria and the yeast population was observed along with the presence of aerobic microorganisms. Under natural fermentation conditions, which were simulated in this study, the team recommends stopping mash fermentation after 550 days because conditions observed in the mash at this time could lead to growth of spoilage microorganisms.

Evelyn Watts is an assistant professor in the LSU AgCenter School of Nutrition and Food Sciences and an AgCenter and Louisiana Sea Grant seafood extension specialist.

(This article appears in the fall 2019 issue of Louisiana Agriculture.)

This is one of the products from the Swamp Dragon Hot Sauce Company, which is one of the more than 400 companies that have been nurtured through the LSU AgCenter Food Incubator.

Figure 1. Aerobic plate count (APC), lactic acid bacteria counts (LAB), yeast counts, tritatable acidity (%TA), and stages during 550 days of red hot chili pepper fermentation. Yellow vertical lines separate stages during pepper mash fermentation.

Figure 2. Changes in volatile compounds during 550 days of natural fermentation of red hot chili pepper mash (a ratio of volatile compound vs. internal standard; VC vs. IS). Yellow lines separate stages during pepper mash fermentation.

Table 1. Six main volatile compounds identified during the 550 days of natural fermentation of red hot chili pepper mash.