Combined Effects of Mild Acidification and Thermal Treatment on Color and Texture of Green Beans

Hurdle technology combining mild acidification (4.6 < pH < 5.0) and reduced thermal treatment could be a potential preservation technique for the production of high-quality processed canned vegetables once it has been microbiologically validated. Freshly harvested green beans were acidified in pre-prepared brine using one of three acidulants (lactic acid [LA], glucono-delta-lactone [GDL], or fermented dextrose containing organic acids), hermetically sealed in cans, and thermally processed in a pilot-scale water-immersion retort. Eight levels of acidulant concentration (0.01–19.5 g/kg) and five levels of desired lethality (0.01–2.74 min) were applied through uniform shell experimental design (Doehlert network method). The color and texture properties of blanched green beans (control samples) and thermally processed green beans with and without prior acidification were evaluated. Statistical analysis showed that acid concentration had a significant effect on color characteristics, and that lethality had a significant effect on texture indices (p < 0.001). Regression models were developed for the prediction of both color and texture properties of thermally processed acidified green beans with two independent parameters: acidulant concentration and lethality.     

Canned Dry Bean Quality as Influenced by High Temperature Short Time (HIST) Steam Blanching

High temperature short time (HTST) steam blanched dry beans had greater drained weights and shear values than water blanched dry beans. Moisture content of dry beans was greater after water blanching. Subjective grade was closely related to drained weights and shear values, and HTST steam blanched dry beans had better subjective grades than water blanched dry beans. Water blanched dry beans were lighter in color than HTST steam blanched dry beans. As length of HTST steam blanch was increased, Agtron color of the beans darkened. High quality canned dry beans can be produced with HTST steam blanching with energy and time savings, but differences between water and HTST steam blanching and canning quality is highly dependent on cultivar and length of HTST steam blanch.     

Ascorbic Acid Retention in Retort Pouched Green Beans

The L-ascorbic acid (AA) retention in and sensory quality of green beans processed under home-canning conditions in retort pouches and metal cans were compared. Green beans processed in cans retained slightly more AA than that processed in the pouches, possibly due to overprocessing of the pouched product. Metal cans offered better AA retention in the green beans than the retort pouches during 11 wk of storage at 21°C, due mainly to a higher rate of AA degradation occurring in the pouched product during the first week of storage. Sensory evaluation showed that the retort pouched beans were significantly better (p < 0.05) than the canned green beans in flavor, texture, and overall acceptance, but not in color.     

Effect of Blanch Temperature on Kinetics of Thermal Softening of Carrots and Green Beans

Cut green beans and diced carrots were blanched at 100°C and 74°C then canned and processed for 5 min to 300 min at 100°C. In every case the rate of thermal softening was consistent with the two substrate first-order kinetic theory of thermal softening of vegetable tissue. The low temperature blanch caused some changes in the apparent firstorder rate constants for both substrates, but the major difference was a much higher intercept of the extrapolated substrate S_S line on the firmness axis. We define S_S at zero process time as the “thermal firmness value” because it is a good indicator of what the firmness of the vegetable will be after canning.     

Vitamin Retention, Color and Texture in Thermally Processed Green Beans and Royal Ann Cherries Packed in Pouches and Cans

Thiamin (B-1) ascorbic acid (AA) and vitamin B-6 (B-6) were determined in pouched and canned green beans immediately after processing and after storage at 24–26°C or 38°C. AA and B-6 were also determined in pouched and canned cherries before and after storage at 24–26°C. There was significantly more B-1 and AA in drained pouched green beans, and more AA in drained pouched cherries than in canned ones. B-6 values in the solids of the pouched and canned products were not significantly different. These three vitamins were significantly reduced in drained pouched and canned green beans after storage at 38°C. B-6 was significantly reduced in the stored cherries. Compared to canned, the pouched products were brighter and firmer in texture.     

Quality Evaluation of Pinto Beans and Green Beans Canned in Two Large Reusable Containers

ABSTRACT: As an alternative to standard metal cans, 2 large-scale, reusable containers were constructed with volumetric capacities 3.6 to 3.8 times greater and process times 1.36 to 2.05 times longer than a nr 10 can. Effects of increased process time on product quality were measured by conducting objective color and texture evaluations on green beans and pinto beans canned in both containers. Green beans and pinto beans had comparable texture profiles to beans processed conventionally in nr 10 cans. The color of green beans also was comparable; the color of pinto beans was darker, possibly due to contact with the metal container. Color and texture differences were minimal between inner and outer product layers.     

β-Carotene and Ascorbic Acid Retention in Fresh and Processed Vegetables

Broccoli, carrots, and green beans (grown in 2 consecutive years) were randomly divided into 3 treatments: fresh-refrigerated (F-R), frozen (FZ) or canned (C) (carrots only). FZ or C vegetables were processed within 24 h and stored for up to 1 yr. F-R vegetables were held at 4 °C for 3 wk (broccoli and green beans) or 6 mo (carrots). Trans b-carotene (Tb-C) and total ascorbic acid (AA) were determined at specified times, before and after microwave cooking. Vitamin content differed between years due to environmental conditions. Blanching resulted in AA loss, but retention remained stable after freezing broccoli and green beans. F-R green beans lost >90% AA after 16 d storage. Linear decreases in AAwere found in most F-R or FZ vegetables. Tb-C decreased slightly during freezer storage. Reductions in Tb-C occurred in canned carrots. Microwave cooking had minimal effects on AA or Tb-C.     

Saponin content of food plants and some prepared foods

Quantitative thin layer chromatography was used to estimate the saponin content of 20 common food plants and also of foods prepared from some of them. The food plants found to be richest in saponins were chickpeas (Cicer arietinum), soya beans (Glycine max), lucerne (alfalfa) sprouts (Medicago sativa) and varieties of Phaseolus vulgaris (navy beans, haricot beans, kidney beans). Saponins were not destroyed by processing or cooking. They were present in falafels (prepared from chickpeas), canned baked beans, canned broad beans and protein isolate from faba beans. However, the saponin content of a fermented soya bean product (tempe) was only half that of whole soya beans. Guar meal (Cyamopsis tetragonolobus) contains saponins but only a trace could be detected in samples of guar gum.     

Low Temperature Blanching Effects on Chemistry, Firmness and Structure of Canned Green Beans and Carrots

Green beans and carrots were canned using extended blanching at 64–65°C and added calcium and/or acid. Firmer products resulted from all treatments but lowered pH was most effective. Blanched green beans were firmer with lower pectin esterification, indicating pectin methyl esterase activity. Green beans and carrots treated with calcium and/or acid and then cooked were firmer than controls. Acid exhibited a firming effect, perhaps by loosening tissue, while calcium reduced the influence of heat. Instrumental bioyield values correlated with sensory results of canned green beans; bioyield may result from a scleriformic layer. Microscopy showed firmer beans had intact middle lamellae while softer samples contained separated cells. These data suggest that the treatments rendered pectates in the middle lamella less heat labile.     

Automated prediction of sensory scores for color and appearance in canned black beans (Phaseolus vulgaris L.) using machine vision

Evaluation of canning quality of beans is commonly carried out by simple visual inspection that is time-consuming, resource intensive, and biased by the experience of the panelist. Moreover, there is not a standard scale to rate visual quality traits of canned beans. In this research, a machine vision system was implemented and tested for automatic inspection of color (COL) and appearance (APP) in canned black beans. Various color and textural image features (average, standard deviation, contrast, correlation, energy, and homogeneity from red, green, blue, lightness, red/green, yellow/blue, hue, saturation and value color scales) were extracted from beans and brine images, and evaluated to predict the quality rates for COL and APP of a group of bean panelists using multivariate statistics. Sixty-nine commercial canned black bean samples from different brands and markets were used for analysis. In spite of the “fair” agreement among the sensory panelists for COL and APP, as determined by multi-rater Kappa analysis, machine vision data based on partial least squares regression model showed high predictive performance for both COL and APP with correlation coefficients of 0.937 and 0.871, and standard errors of 0.26 and 0.38, respectively. When a classification was performed based on both COL and APP traits, a support vector machine model was able to sort the samples into two sensory quality categories of “acceptable” and “unacceptable” with an accuracy of 89.7%. Using simple color and texture image data, a machine vision system showed potential for the automatic evaluation of canned black beans by COL and/or appearance as a professional visual inspection.     

Shrinkage in canned mushrooms treated with xanthan gum as a pre-blanch soak treatment

Vacuum treating freshly harvested mushrooms with a 1% xanthan gum solution (XVT) containing 0.25% sodium metabisulphite (SMBS) prior to blanching and canning gave a lower shrinkage value than for corresponding samples vacuum treated with water, or those canned by conventional means or the 3S process. A combination of chill storage (2-4°C) for 1-3 days coupled with 1% XVT was found best and gave even lower total canning losses (chill storage loss + blanch loss + retort loss); these were 6% lower than in the 3S process and 11.5% lower than for mushrooms canned by the conventional procedure. These data suggest that xanthan gum has considerable potential for reducing shrinkage in canned mushrooms. The XVT canned samples had an excellent colour and an acceptable texture. Further storage tests over a 9 month period with xanthan treated canned mushrooms showed than an SMBS level of 0.1% in the pre-blanch soak solution maintained an excellent colour in the canned product. No in-can mushroom shrinkage took place during the 9 month storage test.     

The peroxidase enzyme activity of some vegetables and its resistance to heat

The peroxidase enzyme activities of some fresh vegetables (cabbage, leeks, carrot, spinach, celery, squash, potatoes, onions and green beans) were determined. The peroxidase activities of cabbage and green beans were high. Onions showed very little peroxidase activity. The vegetables were blanched in hot water at 75°G, 85° and 95°C. Peroxidase inactivation was faster at the higher temperature blanch. Blanching of green beans, potatoes and squash at 75°C for 30 min was not sufficient for complete inactivation of peroxidase enzyme. Peroxidase enzyme inactivation was also affected by the type of vegetable and the size of vegetable pieces.     

Essential Elements and Cadmium and Lead in Fresh, Canned, and Frozen Green Beans (Phaseolus vulgaris L.)

Sixteen essential elements, cadmium and lead were determined in fresh, canned, and frozen green beans (Phaseolus vulgaris L.). Samples were taken during processing to determine where changes in element content occurred. Canned green beans contained lower concentrations of calcium, copper, iron, magnesium, manganese, phosphorus, potassium, and zinc, but had higher amounts of chloride, nickel, and sodium than fresh beans. No change in silicon was observed. Iron, phosphorus and potassium were lower in frozen than in fresh green beans, but calcium, sodium and zinc were higher. There was no change in chloride, copper, magnesium, manganese and silicon due to freezing. Element retention ranged from 51 - 100% for canned and from 73 - 171% for frozen green beans.     

Sensory Evaluation of Tempeh Produced by Fermentation of Common Beans

A tempeh fermented product was prepared from fresh and hard-to-cook (HTC) common beans with the mold Rhizopus oligosporus. Fresh samples fermented for 0, 24 and 48 hr were used to prepare fried tempeh, atoles and cookies at various substitution levels. Atoles were also prepared with fermented hardened beans. A panel evaluated samples for the sensory variables: appearance, odor, color, flavor, texture, and acceptability. For fried tempeh, flavor and acceptability were the sensory variables most affected by fermentation. Atoles, supplemented with fermented fresh and HTC seeds, had significantly lower (P<0.05) flavor and color than controls, respectively. Interestingly, acceptability of atoles, from both fresh and HTC samples, and of cookies was not significantly different (P>0.05) from the controls.     

PILOT PLANT EVALUATION OF INDIVIDUAL QUICK BLANCHING (IQB) FOR VEGETABLES

A pilot plant IQB blancher was field tested at a California freezing plant. The system included: a warming and drying preconditioning unit, a steam chamber for single layer belt heating, a deep moving-bed holding chamber for temperature equilibration and enzyme inactivation and an air-water spray cooling unit. IQB with and without preconditioning were compared to conventional, steam blanching at equivalent levels of enzyme inactivation in green beans, lima beans, Brussels sprouts and green peas. Effluent volume and total-solids concentration were measured. Product yields were determined by measuring residual peroxidase activity, chlorophyll conversion and ascorbic acid content as well as by sensory panel testing for color and flavor. Results showed that vegetables blanched with IQB and IQB with preconditioning were essentially the same in quality as those blanched at commercial conditions. Solids loss in the effluent was substantially less with IQB and preconditioning than with conventional steam blanching     

SENSORY EVALUATION OF CANNED MEAT-BASED FOODS SUPPLEMENTED WITH DRIED DISTILLERS GRAIN FLOUR

Dried distillers grain (DDG) flour was evaluated as an ingredient in canned meat-based foods — beef stew, chili no beans, and hot dog sauce. DDG can be supplemented up to 2.0% in beef stew, chili no beans, and hot dog sauce without significant changes in organoleptic characteristics such as appearance, flavor, mouthfeel, and overall acceptability. DDG may be used as a thickening agent along with modified starch in beef stew. In chili no beans and hot dog sauce, DDG can partially or completely replace texturized vegetable protein, soy or wheat flour.     

Effects of Vacuum Hydration on the Incidence of Splits in Canned Kidney Beans (Phaseolus vulgaris)

Dry red kidney beans were canned using two different pretreatments: soaking for 12 hr at 20°C, and vacuum hydration for 5 min followed by soaking for 2 hr at temperatures from 45-59.1°C. Samples were then packed, processed to commercial sterility, and tested for percentage of split beans after processing. Vacuum hydration pretreatments greatly decreased the incidence and severity of splitting in the canned product and accelerated water uptake while retaining the same moisture content after soaking as the conventional soak treatment. Vacuum-hydrated beans gained less moisture during retorting than conventionally treated samples.     

发酵和焙烤对可可豆多酚、黄酮和风味品质的影响

本实验采用高效液相色谱仪（high performance liquid chromatography,HPLC）、色差仪、电子鼻分别检测未发酵、发酵和焙烤海南可可豆的总酚含量、总黄酮含量、色度和可可豆风味差异。结果表明：未经焙烤的未发酵豆总酚（464.03 mg/10 g）和总黄酮（126.86 mg/10 g）含量明显高于发酵豆总酚（211.86 mg/10 g）和总黄酮（61.98 mg/10 g）含量。105～145 ℃焙烤30 min,未发酵豆总酚和总黄酮含量分别为419.5～129.8 mg/10 g和77.8～16.8 mg/10 g;发酵豆总酚和总黄酮含量分别为182.53～86.25 mg/10 g和34.7～7.0 mg/10 g。其中,125 ℃焙烤20～40 min,未发酵豆总酚和黄酮含量分别为353.74～289.45 mg/10 g和42.86～32.20 mg/10 g;发酵豆总酚和黄酮含量分别为152.08～123.55 mg/10 g和25.12～21.14 mg/10 g。在105～145 ℃的温度焙烤下没食子酸含量变化显著。可可豆色度值的范围：L*值集中在40.0～47.0之间,a*值集中在5.0～6.8之间,b*值集中在4.0～8.5之间。未发酵和发酵可可豆之间,以及不同温度焙烤可可豆之间的电子感官风味分析结果差异较大。     

茄汁三丁黄豆罐头的营养与生产工艺

对制作三丁罐头工艺进行探讨,确定了关键工艺条件及产品质量标准,按该工艺生产的罐头具有良好的品质、口味及耐贮性。