ALBERT

Notizen: Lucerne (Medicago sativa L.) sown at 2·8-11·2 kg ha−1 in spring was thinned in the autumn by digging plants from alternate 15- or 30-cm lengths of row. Both thinning treatments decreased the subsequent year stand density by 34%. Yields the following year were reduced by 24 and 17% for the 15- and 30-cm treatments respectively, and the next year by 10% for both treatments. Thinning effects were similar at all sowing rates. During the year following thinning, plants did not grow larger in response to the thinning. Thus, development of compensatory growth by lucerne plants following sudden stand thinning is slow.

Notizen: The effect of nitrite and storage temperature and toxinogenesis by Clostridium botulinum in vacuum-packed side bacon was investigated. In two series of experiments (A & B) bacon packs were prepared with levels of 0, 50, 100, 150 and 200 ppm nitrite and inoculated with C botulinum at 102 spores/g and 104 spores/g. Packs A were incubated at 20 and 30° C and packs B at 30°C only. Both were held for a maximum of 32 days and analyzed for toxin at intervals of 2, 4, 8, 16 and 32 days. At 20°C none of the controls without nitrite was found to be toxic after 32 days. At 30°C inhibition of toxin formation at the higher nitrite levels was observed at 32 days. Organoleptic evaluation of the bacon packs stored at 30° C showed about one-third of the toxic samples examined were acceptable to the panel.

Notizen: Six annual legumes were evaluated as components of cereal-grass-legume intercrops in two experiments at two sites differing in elevation by 789 m. Barley (Hordeum vulgare L.) and Westerwolds rye-grass (Lolium multiflorum Lam.) were seeded on all intercrop plots. Dry-matter (DM) yield, crude protein (CP) and organic matter digestibility (OMD) were measured. DM yield and N content were used to estimate legume N fixation. Experiment 1 was conducted at both sites. At the lower site, Persian clover (Trifolium resupinatum L.) and annual alfalfa (Medicago sativa L.) accounted for 70% of the DM yield in harvest 1 (July), increased CP and OMD, but did not affect intercrop yield. They increased harvest 2 (August/September) intercrop yield by 263% and CP concentration by 65 g kg−1 DM. They increased harvest 3 (October) yield by 275% and CP concentration by 78 g kg−1 DM. Inclusion of striate lespedeza (Lespedeza striata) did not affect intercrop yield or quality. Annual legumes failed to establish at the higher elevation site and therefore had no effect on DM yield or forage quality. In Experiment 2, in which the performance of Westerwolds ryegrass was also compared with that of Italian ryegrass, and conducted at the lower site only, Persian clover and berseem clover (T. alexandrinum L.) increased CP of all three of the year's harvests. These two species contributed 29% of the DM yield in the first harvest (July) but did not affect total intercrop yield. They increased harvest 2 (August) yield by 313%. Persian clover increased harvest 3 (October) yield by 318% and berseem clover increased harvest 3 yield by 405%. Barrel medic (Medicago truncatula) and snail medic (M. scutellata) contributed 29% of harvest 1 yield, and increased both DM yield and CP content. Medics did not regrow. Aubade Westerwolds ryegrass contributed a greater percentage of the DM yield than did Maris Ledger Italian ryegrass at harvests 1 and 2. Ryegrass type did not affect total DM yield but did affect forage quality; intercrops containing the Italian ryegrass had higher CP at harvest 2 and higher OMD at harvest 3 than those containing the Westerwolds ryegrass. Over both experiments, at the lower elevation site, stands with Persian clover, berseem clover or alfalfa produced 80% of the yield of barley-ryegrass receiving 250 kg N ha−1, and 165% of the yield of unfertilized barley-ryegrass. Berseem and Persian clover fixed about the same amount of N over the growing season; 188 kg N ha−1 in Experiment 1 and 134 kg N ha−1 in Experiment 2.

Notizen: Methods were determined for the induction of diploid gynogenesis in the sole, Solea solea (L.), in order to investigate the sex-determining mechanism. The experiments utilized gametes obtained by dissection of fish caught at sea. Activation of eggs with UV-irradiated sole sperm was not feasible but development was initiated by exposure to halibut, Hippoglossus hippoglossus (L.), sperm. These embryos displayed the typical characteristics of haploids and few survived beyond hatching. High levels (〉 90%) of diploidy were induced in such eggs by subjecting them to a cold shock (2°C or 4°C) for 1-2 h about 10-15 min after activation at 12°C. The resultant embryos were indistinguishable from those developing from normally fertilized eggs and were considered to be diploid gynogenomes. Fifteen of these were reared to a length of 5-10 cm by which time gonad differentiation had been initiated. Both sexes were represented, indicating that sex in this species is not determined by a simple XX-XY system with female homogamy.

Notizen: A pilot scale study was conducted to measure soluble solid losses of early June, mini and medium sweet peas commercially blanched at 95 ± 1°C for 3 min using a 25 lb (11.34 kg) sample size. Early June peas had smaller losses than mini and medium sweet peas. Dry matter losses were the greatest for the smallest sizes in each variety. Moisture content did not change significantly during blanching but increased after canning. Alcohol Insoluble Solids increased for all sizes in each cultivar after blanching. Recovery of small size peas may be maximized by bypassing blanching and gravity separation.

Notizen: Taste panel results indicated that the warmed-over flavor of turkey meat was readily detectable and was equally detectable in both white and dark meat. Statistical analysis of gas chromatographic flavor profiles comparing fresh and reheated turkey meat selected three components of the profile as being correlated to the warmed-over flavor. The three components were found to increase due to reheating. Two of the three were identified as heptanal and n-nona-3,6-dienal. The remaining compound could not be identified. The two known compounds are typical end-products of lipid oxidation which further supports the hypothesis that warmed-over flavor is due to lipid oxidation.

Notizen: Available lysine losses in soy protein isolates during thermal processing go through three phases: a fist-order loss, a transition phase and a no-loss phase. The transition phase shows a statistically significant (P 〈 0.02) increase in available lysine when measured by the fluoro-dinitrobenzene (FDNB) method. Using the protein efficiency ratio method (PER), a statistically significant (P 〈 0.1) increase in available lysine was demonstrated in samples processed at 80° C for 700 mm. The PER values decreased from 2.65 ± 0.04 to 1.17 ± 0.04 after 600 min of processing. At 700 min the PER value increased to 1.37 ± 0.05. At 80°C the transition phase in systems containing 4% sugar occurs 600 mm after processing is initiated according to previously published equations. The PER and FDNB results exhibited an excellent correlation (r = 0.98). Thus, PER results confirm the increase detected using the FDNB procedure.

Notizen: An improved muscle protein solubility method has been developed which has two distinct advantages over the traditional method: it requires much less time and may be conducted at room temperature. The pre- or post-rigor sample is homogenized in a Brinkman Polytron in 25 ml buffer and is centrifuged. The supernatant is decanted and soluble protein determined as in the traditional method (biuret). Comparable results were obtained for old vs new method for samples of porcine longissimus muscle which encompassed a wide range of sarcoplasmic and myofibrillar protein solubilities. The new method can also be applied with accuracy equivalent to the traditional method for the determination of solubility in cooked meat samples. A four-factor response surface experimental design (central composite) was utilized to evaluate the role of process variables and product ingredients on the cooking losses of USDA Utility grade biceps femoris muscle. The factors were cooking time (0.5–12.0 hr), temperature (55–85°C), NaCl (0–4%), and Na tripolyphosphate (0–0.5%): Shrink was determined on ground 25-g samples by calculating the free moisture lost (as a percentage of total moisture) after centrifugation in Wierbicki tubes. Sarcoplasmic and myofibrillar protein solubility were determined on the same samples by the rapid solubility technique. Stepwise regression was used to tit a multiple polynomial equation to shrink loss and protein solubility (P 〈 0.001). The results indicated that cooking temperature was decisively the most important factor controlling yield and protein solubility. Shrink and protein solubility were nearly independent of time in the center point regions of the experiment which are, based on the type of design (central composite), the most accurate areas for prediction. Previous studies have demonstrated that the major tenderization reactions in beef are dependent both on time and temperature. Therefore, these findings suggest that improved yield in commercial thermal processes is possible by selecting long-time, low-temperature treatments since protein solubility and, therefore, yield are primarily functions of temperature and are relatively independent of time at a given temperature.

Notizen: This study was conducted in order to develop a mathematical model for predicting lysine losses during processing of soy products. Model systems used in this study consisted of micro crystalline cellulose, glucose, sucrose, potato starch and soy protein. System composition, water activity, pH and time and temperature of heating were varied and available lysine was monitored by the fluoro-2,4-dinitro benzene method of Carpenter. In the first set of experiments, statistical analysis of the data obtained resulted in an equation which shows the effects of the variables used on available lysine retention: Fraction available lysine remaining = 0.58 + 0.047 pH - 0.093 glucose - 0.059 temperature —0.0068 time + 0.031 (water activity)2+ 0.025 aw sucrose + 0.033 sucrose starch. These data were collected at heating times well in excess of that required to destroy all reducing sugars present. Heating times were reduced in the second experiments such that kinetic data could be obtained. The average Ea was 28,500 calories/mole°K and the average reference reaction rate at 100°C (K100) was 0.036 mg lysine/min.

Notizen: The effects of freezing (still-air, air-blast, and Freon immersion freezing) and frozen storage (−5°, −10° and −15°C for 0 to 48 wk) on texture of cooked frozen peas were examined. Peas frozen by a Freon-12 immersion method with no appreciable damage to cell structure had firmer and more chewy sensory textural quality compared to those peas frozen by a slower freezing method. Sensory tenderness decreased initially and then increased with storage time to the maximum storage times of 6 wk in −5°C storage, 16 wk in −10°C storage, and 48 wk in −15°C storage. Sensory chewiness increased initially, then remained constant with storage time except in −15°C storage. Generally, the lower storage temperature resulted in less sensory chewiness. The correlation coefficients (r) between sensory and objective measurements for tenderness and chewiness were 0.76 and 0.88 (P 〈 0.05), respectively.