This study examined the role of nitric oxide (NO) in tonic inhibition of motor activity in isolated, perfused canine ileal segments. Brief addition of N omega-nitro-L-arginine methyl ester (L-NAME) to the perfusate caused, after a delay, a concentration-dependent persistent increase in tonic and phasic activity of circular muscle. This increased motor activity was prevented or reversed by addition of L- but not D-arginine to the perfusate. Removal of Ca2+ or addition of 10(-7) M omega-conotoxin (GVIA) to the perfusate markedly reduced this response. The motor activity induced by L-NAME was accompanied by loss of distal inhibition and enhanced excitation to low-frequency field stimulation. L-NAME infusion significantly reduced tonic vasoactive intestinal polypeptide (VIP) output, sodium nitroprusside increased VIP output, but L-arginine infusion did not restore VIP output. Atropine (10(-7) M) and/or hexamethonium (10(-4) M) reduced the motor response to L-NAME by 75%. Atropine reduced and hexamethonium nearly abolished VIP output. We conclude that there is tonic Ca(2+)-dependent NO output from perfused intestinal segments dependent on nerves with N-Ca channels, that NO acts to inhibit muscle directly and by inhibiting release of excitatory mediators, and that this output is the primary inhibitory determinant of contractile activity.

Effects of temperature and time postmortem on the thermal conductivity of white and dark chicken meat were studied using a line heat source thermal conductivity probe to measure thermal conductivity. The effect of time postmortem was determined at body temperature and 20° C by leaving probes in whole birds for periods of 1–2 days; time postmortem had no significant effect. The effect of temperature was studied at temperatures of 20, 10, 0, −10, −20, −40 and −75°C using cylindrically shaped samples 3/4 in. in diam × 11/2 in. long. 48 samples were used from 24 7‐lb cockerels. Three thermal conductivity measurements were made on each sample at each temperature level. The effect of temperature was similar to that reported in the literature for other meats. The following equations may be used to express the results obtained for white meat: k(Watt/m‐°C) = 0.476 + 0.00060T(°C) (0–20°C) and k(Watt/m‐°C) = 1.07 − 0149T − 1.04 × 10−4T2(−75 to −10°C). Similar expressions were obtained for dark meat.

A new method of preparing laboratory meat emulsions utilizing the concept of continuous-flow emulsification was developed to simulate industrial conditions. High speed centrifugation was used to separate phases of preblends and emulsions for the investigation of protein solubility Studies of the effect of water:meat ratio on the protein solubility or preblended and emulsified meat indicated that increasing water:meat ratios resulted in preblends and emulsions with larger soluble phases and lower soluble protein concentrations in the soluble phase. The effects of preblending method, temperature of meat prior to preblending, level of added water and temperature of the added water on the temperature of preblends and emulsions, protein solubility, NaCl concentration, cooked emulsion stability and firmness of the cooked emulsions were established. Temperature of the meat (-30, -10 or 0°C) accounted for the largest proportion of the variation in temperature of preblends and emulsions, protein solubility and cooked emulsion stability. Lower temperatures in preblends and emulsions were associated with the colder meat temperatures. The data indicated that emulsions prepared with -10°C meat had the poorest cooked emulsion stability as compared to those prepared with -30 and 0°C meat. Level of added water (10, 20, 30 or 40%) significantly affected the temperature of preblends, protein solubility, cooked emulsion stability and firmness of the cooked emulsions. The 10% level of added water resulted in firmer emulsions with greater cooked stability. Temperature of the added water-(0, 30, 60, or 90°C) had a significant effect on the temperature of preblends and emulsions, cooked emulsion stability and firmness of the cooked emulsions. Adding 90°C water resulted in emulsions with the poorest cooked stability while adding 0°C water resulted in firmer cooked emulsions.

Restructured scallops (Argopecten gibbys) were prepared with two cold‐set binders: 1% concentrations of alginate and microbial transglutaminase (MTG), with setting times of 2, 6, 9, 12, 18 and 24 h at 5C. Apparent modulus of elasticity, 5% secant modulus, 10% secant modulus and 20% secant modulus were used to evaluate the effect of setting times on the binding strength of restructured scallops. The binding strength as measured by the 5, 10 and 20% secant modulus was not significantly different (P > 0.05) in MTGase‐restructured scallops, but significantly different in alginate‐restructured scallops at 5 and 10% strain. Apparent modulus of elasticity showed significant differences in the binding strengths (P < 0.05) of restructured scallops prepared from both binders. The alginate gel restructured scallops achieved a binding strength of (158.7 kPa) in a 2‐h setting, while MTG‐restructured scallops reached a binding strength of (336.0 kPa) at a 24 h setting.

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