热水处理对鲜切马铃薯生理和品质的影响

以鲜切马铃薯为试验材料,研究鲜切马铃薯在35℃10 min的热水处理和对照组(CK)下生理指标和品质指标的变化。结果表明:在低温(4℃)贮藏条件下,35℃10 min的热水处理显著抑制了鲜切马铃薯的失重率和呼吸强度,维持了较高的白度和可溶性固形物含量,有效地保持了细胞膜的完整性,抑制了多酚氧化酶(PPO)和过氧化物酶(POD)的活性,从而改善了鲜切马铃薯的贮藏品质,延缓了鲜切马铃薯的褐变。     

热杀菌方式及储藏条件对熟制甘薯品质的影响

主要研究了热杀菌方式、包装与储藏条件对熟制甘薯品质的影响。以经烤箱熟制后的优质甘薯为原料,在不同的热杀菌方式、包装和储藏条件下,对其失重率、感官品质、老化程度和微生物繁殖状况等进行了研究。结果表明,厚度为0.12 mm的真空包装袋对熟制甘薯失重率影响较小,保水性能最佳;熟制甘薯在-18℃冻结储藏60 d时,细菌和霉菌计数仍未超标;在2～4℃冷却储藏9 d的熟制甘薯糊化度较低,淀粉老化程度相对较高。     

新型高蛋白富硒叶面肥对潍县萝卜品质影响

目的：利用研发的新型高蛋白富硒叶面肥,以潍县萝卜为载体,通过人工措施对萝卜进行叶面喷洒施肥,达到提高萝卜品质和给人补硒的目的。方法：对富硒萝卜和普通萝卜进行对照试验,按照国家最新发布的标准方法,测定分析其营养成分、氨基酸组分、矿物质元素和维生素等。结果：高蛋白富硒叶面肥更容易被潍县萝卜吸收,产出的萝卜不仅硒的含量高,而且其它指标均高于普通萝卜。     

冷冻对马铃薯品质的影响

新鲜马铃薯在-20℃冷冻24h,然后在20℃解冻1h,接着对其组织状态、Vc流失、酶促变色和矿物质含量等指标进行测试分析,并与未经冷冻处理的对照组进行比较,以研究冷冻对马铃薯品质的影响。     

Effects of High CO_2 Pretreatment on the Quality of Fresh-Cut Potatoes

Effects of short-term high CO_2 pretreatment on quality of fresh-cut potatoes were studied. Potatoes were treated under 90% CO_2 for 18 h, peeled, cut, dipped in 1% ascorbic acid or distilled water for 3 min, packed in polyethylene bags and stored for 12 d at 4 ℃. Non-treated potatoes were used as the control. High CO2 pretreatments ensured maintenance of a high level of CO_2 in headspace of packages containing fresh-cut potatoes. Both the growth of total aerobic bacteria in initial stages of post-cut storage and browning index of the cut surface were lower in high CO_2 treated cut potato. Anti-browning effect of high CO_2 pretreatment was decreased when applied in combination with ascorbic acid. Soluble solids, pH, titratable acidity and flesh firmness of fresh-cut potatoes were not affected by high CO_2 treatment. Therefore, high CO_2 treatment before slicing could be effective method to maintain quality of flesh-cut potatoes.     

Effect of Packaging Materials on the Chemical Composition of Potatoes

Russet Burbank and Chieftain potatoes were packaged in either mesh, paper or polyethylene bags and compared in chemical composition after 1, 4, and 8 wk of storage at 20^oC. Potatoes were analyzed for weight loss, discoloration, phenols, ascorbic acid, glycoalkaloids and nitrate-nitrogen. Potatoes packaged in polyethylene were lowest in weight loss, ascorbic acid and nitrate-nitrogen and highest in discoloration, phenols and glycoalkaloids than those packaged in mesh or paper. Potatoes packaged in paper were lowest in discoloration and phenols and highest in ascorbic acid. There were no significant differences in weight loss, glycoalkaloids or nitrate-nitrogen between potatoes packaged in mesh on paper.     

Effect of Molybdenum Fertilization on the Nitrogenous Constituents of Potatoes

The effect of molybdenum fertilizer on the nitrogenous constituents of Katahdin potatoes was investigated. The chemical constituents studied were total nitrogen, nonprotein nitrogen, and protein. Sodium molybdate was applied to the soil at rates of 0.0, 2.8, 6.7 and 10.1 kg/ha during the first year and 0.0, 5.6, 16.8 and 22.4 kg/ha during the second year of the study. The compound was applied to the soil one day prior to planting of the seed potatoes. During both years of the study, tubers from plants receiving molybdenum fertilization were significantly higher (p < 0.01) than the controls in total nitrogen and protein and significantly lower (p < 0.01) in nonprotein nitrogen at all levels of molybdenum application. Greatest increases in total nitrogen and protein were observed in tubers from plants receiving 22.4 kg/ha of sodium molybdate.     

Effect of Mechanical Injury on the Ascorbic Acid Content of Potatoes

Effects of two types of mechanical injury (wounding and bruising) on the ascorbic acid content of Belrus cultivar tubers were compared. Wounding involved cutting slices (1 mm) and strips (10 × 20 mm) and both slices and strips exhibited a highly significant increase (p < 0.01) in ascorbic acid following wounding. The largest increase (400%) occurred in slices after 2 days. Ascorbic acid decreased significantly (p < 0.05) in the bruised halves as compared with the unbruised halves. Maximum decrease in ascorbic acid (347%) of bruised tissue occurred after 2 days storage at 5°C. The unbruised halves appeared to synthesize ascorbic acid when compared with the controls, the maximum increase (144%) occurring after 2 days storage at 5°C.     

Quality of French Fried Potatoes as Affected by Surface Freezing and Specific Gravity of Raw Potatoes

Russett Burbank potatoes were stored at 7.2°C for 9 months and processed into French fries. Some of the potato strips were subjected to partial freezing at – 20°C for 25 min before water blanching for surface leaching. The samples treated by partial (surface) freezing generally absorbed more oil during par-flying but less oil during finish-frying compared to the untreated samples (control). French fries made from partially frozen potato strips contained less reducing sugar and ascorbic acid and were lighter in color than the control. Darker fries were produced from potatoes of lower specific gravity because of the higher reducing sugar content. The surface freezing treatment was an effective means of decreasing oil absorption and improving color of French fries.     

松粉机对物料品质的影响

在制粉过程中,松粉机的使用日渐普遍.它占用空间小,耗电能低,撞击粉碎效果好等优点已为人们普遍认识.但若使用不当,也会影响到制粉效果.笔者对安装位置不同的松粉机的工艺效果进行了测定分析,并进行了对比研究:     

Effect of Irradiation on Discoloration, Phenols and Lipids of Potatoes

The effect of two irradiation doses, 10 and 100 krad, on discoloration, phenolic content and lipid content of Katahdin and Russet Burbank potatoes was studied. Potatoes were stored 1, 4 and 26 wk at 5°C and 20°C following irradiation. Irradiation increased discoloration and phenols and decreased crude lipids and the phospholipids. Potatoes receiving 100 krad dose discolored more, were higher in phenols, and lower in lipids than those given 10 krad dose. Potatoes stored at 5°C discolored more and were higher in phenols and in lipids than those stored at 20°C. Increased storage at both temperatures resulted in greater discoloration, increased phenolic content and decreased lipids content.     

Effect of Packaging Material on Nitrate Nitrogen Content of Irradiated Potatoes

The effect of packaging materials on nitrate nitrogen content of irradiated potatoes was investigated. Tubers were irradiated at 10, 30 and 100 Krads and stored for 12 wk at 5°C in paper or plastic bags. Nitrate nitrogen content was significantly (p < 0.01) higher in tubers packaged in plastic as compared to those in paper bags. Irradiation significantly (p < 0.01) increased nitrate nitrogen content between the lowest and highest levels of treatment in tubers stored in both paper and plastic bags.     

采收前叶面喷施微生物制剂改善烟叶品质试验

为改善烤烟上部烟叶的内在品质,将由烟田土壤中分离筛选的有益微生物(经鉴定,为巨大芽孢杆菌)制得的微生物制剂,于采收前10d喷施在K326上部6片烟叶的叶面上,用量分别为50和100mL/667m2,成熟采收,取初烤烟叶进行重要香味成分、氨基酸、蛋白质含量分析和评吸。结果表明:与对照相比,喷施该制剂的烟叶的重要香味成分含量明显增加,氨基酸总量和蛋白质含量均有所降低,吸味品质明显改善。     

小麦芽粉的应用对面包品质影响的研究

研究探讨了小麦芽粉的添加量对面包品质和面团粉质性能的影响以及小麦芽粉面包的生产工艺.实验结果表明:小麦芽粉的的使用对面包的品质具有一定的改善作用,经过烘烤处理的小麦芽粉在面包生产中的最适宜添加量为6%～8%;通过正交实验得出了麦芽面包的最佳生产工艺条件.     

Effect of Baking and Frying on Nutritive Value of Potatoes: Minerals

The effect of conventional baking and frying on the mineral content of Katahdin, Chipbelle and Rosa varieties of potatoes was investigated. The cortex and pith tissues of the tubers were used. Conventional baking reduced the cortical content of potassium, phosphorus, and iron by 10–13%, 4–21%, and 19–31% respectively. In all three varieties, movement of potassium, phosphorus, and iron toward the interior tissues was demonstiated during conventional baking although varieties varied widely in their mineral content. Conventional baking increased the pith content of potassium (14–23%), phosphorus (2–9%), and iron (2–8%). Frying decreased significantly all the minerals in both the cortical and pith areas with the major loss occurring in the cortical area (10–45%).     

Effect of Irradiation on Total Glycoalkaloids in Kennebec and Russet Burbank Potatoes

Effect of irradiation and storage conditions following irradiation on total glycoalkaloids (TGA) of Russet Burbank and Kennebec potatoes stored 4 and 12 wk was investigated. TGA increased significantly (p < 0.005) immediately following irradiation in both cultivars, but decreased upon storage. TGA was higher in Kennebec than Russet Burbank often exceeding levels considered safe for human consumption. At 5°C TGA was higher in tubers stored in paper as compared to polyethylene, while at 20°C this was reversed.     

Effect of Baking and Frying on Nutritive Value of Potatoes. Nitrogenous Constituents

The effect of conventional baking and frying on the content of total and nonprotein nitrogen of Katahdin, Chipbelle and Rosa varieties of potatoes was investigated. The cortex and pith tissues of the tubers were analyzed separately. In cortex tissue, baking reduced the total nitrogen (5–18%) and total amino acids (5%). In pith tissue, baking increased total nitrogen (3–20%), nonprotein nitrogen (9–28%), and total amino acids (13%). During baking migration of nitrogen constituents from cortex to pith tissue occurred in all three varieties. In cortex tissue frying decreased significantly the total nitrogen (29–43%), nonprotein nitrogen (20–35%) and amino acid content (45%). A similar trend was observed in the pith tissue. Greater losses in total, nonprotein nitrogen and amino acids occurred with frying than with baking.     

Effect of Curing on Sensory Properties and Carbohydrate Composition of Baked Sweet Potatoes

In a two-year study, the flavor and texture profiles and carbohydrate composition of cured, baked‘Jewels’sweet potatoes were compared to baked, uncured‘Jewels’sweet potatoes. Curing increased the rate of production of flavor notes and only slightly influenced development of “moist” mouthfeel. Given sufficient time after harvest, baked, cured roots were indistinguishable from baked, uncured roots. Carbohydrate content was not a sensitive indicator of post-harvest treatment since no statistically significant differences were detected between cured and uncured roots.     

Effect of Ammonium Nitrate and Low-Level Foliar Treatments of Simazine on Some Chemical Components and Protein Quality of'Pinkeye Purple Hull' Pea Seeds

Southern pea seeds were grown 2 yrs with treatments of ammonium nitrate fertilizer 0, 30, and 60 kg/ha and simazine 0, 2,000, and 4,000 ppm applied as a foliar spray. Yield, proximate analysis, amino acid content, and protein quality were determined. No differences were found in yield, crude fat, and crude fiber. Ash, protein, and several of the amino acids increased with the 30 and 60 kg/ha nitrogen fertilizer treatments. Treatments with simazine had no effect on the essential amino acid content. In the Southern pea seeds, protein quality was decreased by the treatments with nitrogen fertilizer, simazine, and combinations of these treatments.