570 t. Milk Food Technol., Vol. 37, No. 11 (1974) EFFECT OF FERMENTED MEAT pH ON SUMMER SAUSAGE PROPERTI ES' J. C. Acrox AND J. E. KELLER" Department of Food Science Clemson University, Clemson, South Carolina 29631 (Received for publication March 29, 1974) ABSTRACT phase. The water holding capacity of muscle pro­ Downloaded from http://meridian.allenpress.com/jfp/article-pdf/37/11/570/2399586/0022-2747-37_11_570.pdf by guest on 26 September 2021 Beef summer sausages were fermented to pH endpoints teins is at a minimum at the isoelectric point (10). ranging from 5.5 to 4.6. A nonfermented sausage of pH 5.9 Acton et al. (1) reported that fermentation of sum­ served as control. Fermentation time requirements using a mer sausage at either 22, 30, or 37 C did not sig­ frozen concentrate of Pediococus cereuisiae ranged from 7-8 nificantly affect product flavor although less lactic h (pH 5.5) to 19--21 h (pH 4.6). Water holding capacities (WHC) of sausage mixes during the fermentation phase acid was produced at 22 C than at 30 or 37 C. Lactic rapidly decreased as sausage pH decreased, reaching a mini­ acid imparts the characteristic "tangy" flavor of fer­ mum at pH 5.2. An increase in WHC from pH 5.2 to pH 4.6 mented sausages (6, 19, 24). An acid content of 0.5 was attributed to the combined effect of pH reduction and re­ to 1.5% is generally reported for summer sausage, cer­ maining functional protein. Bacterial counts (total viable and lactic bacteria) showed a stepwise increase from 2.4 X 10e velat, and thuringer (1, 19, 23). cells/g (lactics) to 6.6 X 10" cells/g (lactics) during ferment­ The solubility of meat proteins (15, 23), inhibition ation. Reductions of bacterial counts during heat processing of pathogenic microorganisms (7), use of freeze-dried appeared dependent on the sausage pH and phase of bac­ meat (18), and compositional changes during the fer­ terial growth. Compositional changes (fat, protein, ash, salt, lactic acid) during the drying phase were significantly corre­ mentation and processing of fermented-dried sau­ lated to moisture loss of the sausages. Within drying intervals sages have been investigated. ( days), sausages of pH groups 5.9 and 5.5 had significantly This study was done to evaluate the effect of the less weight loss and required lower shearing force when com­ pH attained during summer sausage preparation on pared to pH groups 4.8 and 4.6. For summer sausages exam­ ined at 20 days of drying, panelists rated higher preference (a) water holding capacity of the sausage mix, (b) and "tangmess" scores as sausage pH decreased. bacterial counts on heat processing, (c) sausage weight loss ("shrinkage"), and (d) textural development dur­ Fermented sausages possess good keeping qualities ing drying. Compositional changes during drying because of low pH and high salt content, and, in dry varieties, a low moisture content. Traditional pro­ and taste panel evaluation of product flavor were also duction processes require 3 to 5 days for fermentation determined. and processing before drying. Use of commercial MATERIALS AND METHODS starter cultures of Pediococcus cereoisiae and Lacto­ bacillus plantarum in frozen concentrate form has Sausage preparation and processing significantly reduced fermentation time requirements A summer sausage formulation (Table 1) was used in this study. Fresh boneless beef (chucks) was obtained from the to 15 to 24 h (2, 8). The controlled inoculation of state-inspected Meats Laboratory of the Animal Science De­ lactic bacteria aids processors in maintaining uniform partroent at Clemson University. The boneless beef was product characteristics from batch to batch (8, 19, 21). coarsely ground once through an 8-mm plate, mixed, and The fermentation phase is sometimes referred to as reground through a 6-rom plate. Packages of approximately 4.54 kg of meat were frozen at -20 C for 2 to 3 months. the "ripening" period (16). Thawing was done at room temperature (21 C) for 10 to The pH generally attained during fermentation is 12 h followed by 6 to 8 h storage at 0 C. Proximate compo­ near 5.1 although a lower pH is desired for some sition of the ground meat was 63.6% moisture, 16.9% protein, products (16, 19). Final retail products range in pH 17.3% fat, and 0.9% ash. from 4.8 to 5.4 (24). The isoelectric point of meat Sausage mixes were prepared by blending in a Hobart 4346 Mixer-Grinder equipped with two arm paddles. The curing proteins (near 5.0) is approached in fermentation agents, seasonings, and dextrose were blended into the meat which aids. in moisture removal during the drying for 4 min before addition of the starter culture. A suspension of Pediococus cereoisiae (LACTACEL, Merck & Co.) was added at a level of 2.4 X 10e cells!g meat and the meat mix­ 'Technical Contribution No. 1165 of the South Carolina Agri­ ture blended for an additional 6 min. The initial mix tempera­ cultural Experiment Station, Clemson University, Clemson, ture was approximately 2 C and increased to approximately South Carolina 29631. 10 C during the 10 min of blending at 29 rpm, Two replicate "Present address: The Blue Channel Company, Division of sausage batches were prepared in different weeks using the Alexander Dawson, Inc., Port Royal, South Carolina 29935. same lot of boneless beef, 571 Water holding capacity EXTRACT RELEASE Sausage samples were evaluated during fermentation for 25 , VOLUME water holding capacity (WHC). Two methods were utilized, 20 an extract release volume (ERV) method and a centrifugation >- procedure. I- O~ U 15 The ERV method of Acton et al. (1) as modified from the initial procedure of.Jay (12) was used for WHC determinations. f 0 O~ ~ ERV results were expressed as ml bound/l0 g meat. <C -III 10 u E A centrifugation technique modified £rom Hamm (10) as re­ (!) 01 5 0-- ported by Wardlaw et al. (22) was also used to determine z Q WHC. The WHC with this method was also expressed as ml B ...... 01 I' L---I bound/l0 g meat. ....I "0 0 r:: ::r:: :::l Plate counts 4.0 CENTRI FUGATION Downloaded from http://meridian.allenpress.com/jfp/article-pdf/37/11/570/2399586/0022-2747-37_11_570.pdf by guest on 26 September 2021 .8 Counts of total viable bacteria and of lactic acid bacteria 0::: ., , w E 3.0 , , were made on sausage samples at the fonowing intervals of processing: (a) after initial blending of ingredients but before ~ " ~ .. 5: 2.0 " " ............... starter culture addition; (b) after inoculation and final blend­ ing of the sausage mix (pH of 5.9); (c) on attaining pH values .-----.--- -- of 5.5, 5.2, 4.8, and 4.6; (d) after heat processing' each pH 1.0 group to 60 C internal; and (e) after 20 days of drying. 0.0 Duplicate samples of 20 g of meat were blended with 180-ml quantities of 0.9% saline and subsequent decimal dilutions were prepared with the same diluent Duplicate I-ml samples of 6.0 5.6 the appropriate dilutions were mixed with standard plate count agar (3) for total viable bacteria and the V-8 agar of MEAT pH Fabian et al (9) :fqr lactic acid bacteria. Plates were incubated at 80 C for 48 to 72 h before counting. Figure 1. Rate of pH reduction during fermentation, of summer sausage. Sausage composition PeIl'centages of moisture, fat, protein, ash, and salt were Each sausage preparation was stuffed' into 52 mm diameter determined for the initial sausage mixes and the products dur­ D.S. fibrous casings (Union Carbide). The sausage chubs, ing drying. Moisture, fat, and ash were determined by AOAC each weighing approximatelyo 540 g, were hung in a fermen­ (4) methods. The Kjeldahl nitrogen method following AOAC tation chamber maintained at 38 C and 95% relative humidity. (4) was used for protein analysis. Total nitrogen obtained by One group of 12 chubs was not fermented but carried im­ Kjeldahl analysis was corrected for nonprotein nitrogen using mediately through heat proCessing as described below. Dur­ 5% 'trichloroacetic acid filtrates. The salt content, expressed ing the time course of fermentation, the meat pH was period­ as NaCl, was measured with QUANTAB Chloride Titrators ically monitored by examining randoml.yo selected sausage chubs fonowing. the procedure of the AOAC (5) and Vander Werf £rom the chamber. As the pH decreased by 0.2 to 0.4 pH and Free (25). unit, a set of. 12 chubs were removed for immediate heat pro­ Weight 1088 and shear measurements cessing. Fermentation was terminated as close as possible at the following pH values: 5.5, 5.2, 4.8, and 4.6. The initial The percent weight loss or "shrink" of summer sausage chubs was determined after 8, 5, 8, 10, 15, and 20 days of drying. sausage group of the nonfermented mix had a pH of 5.9. It each Should be noted that approximately the same pH values were Five sausage chubs from pH group were selected after used for fermentation termination in the second replicate heat processing for weight recording on drying. batch of sausages (Fig. 1). Approximate time requirements Shear forces' for slices of the sausage samples were measured to reach these pH endpoints are also given in Table 2. with an ADo-Kramer Shear l.4ress equipped with a 3000-lb ring. For heat processing, the sausage chubs were initially placed The press was operated at a downstroke of 30 sec and range at 82 C for 2 h and then at 88 C until an internal temperature 800.