Processing to Improve Quality of Dehydrated Precooked Pinto Beans

The firmness of precooked and rehydrated beans after soaking in water at 30°C/2 hr and 82°C/1 hr was lower than that after soaking at 82°C/1 hr or 22°C/12 hr. The 22°C/12 hr soaking yielded the lowest butterflying (8.0%). Steam precooking at 100°C/1 hr produced less splitting, lighter color, and firmer texture than pressure precooking. High initial humidity dehydration reduced splitting. Beans after soaking at 30°C/2 hr and 82°C/1 hr, precooking at 100°C/1 hr, and dehydrating at 65°C/6 hr with initial 95% relative humidity were better regarding firmness, butterflying (11.6%), and moisture content (10.4%).     

Hydration Kinetics of Red Kidney Beans (Phaseolus vulgaris L.)

Soaking of dry red kidney beans was studied at 20, 30 40 and 60°C by the method of weight gain until equilibrium conditions were attained. Water absorbed during soaking was a function of both soaking time and temperature. Soaking at high temperatures increased the hydration rate constant and decreased soaking time to achieve equilibrium. Compared to unblanched beans, the application of a pre-blanching step considerably reduced hydration times of blanched beans. Due to the plasticity effect acquired upon blanching, blanched beans showed a significantly high hydration rate constant and exhibited a more constant equilibrium moisture content regardless of soaking temperature. Activation energy values (E_a) of the hydration process were 6.48 Kcal/mole for blanched and 14.25 for unblanched beans.     

Effect of Heat Processing on Hemagglutinin Activity in Red Kidney Beans

The effect of temperature in destroying the hemagglutinin (lectin) activity in red kidney beans has been determined. Heating presoaked beans at 100°C for 15 min or at 80°C for 2 hr, or pressure cooking (15 psi) foi 45 min without presoaking, decreased the hemagglutinin activity to below detectable levels. At 65°C, no significant decrease was observed even after 12 hr heat treatment. Commercially canned beans have lectin levels similar to beans pressure cooked for 30 min.     

Rapid Rehydration Methods for Dried Beans

Rapid methods of rehydrating dried kidney, pinto or navy beans by soaking at 82°C or 93°C for 5, 10 or 30 min were compared to standard 18 hr soaking at ambient temperature. Canned beans processed 21 min at 121°C had higher drained weights and softer texture with fewer split beans than those processed 41 min at 116°C. Kidney, pinto and navy beans soaked 30 min at 82°C had higher drained weight than those soaked 30 min at 93°C. Hydration coefficient (2.07) of controls (18-hr soak) and beans soaked 82°C (1.94) or 93°C for 30 min were not different. Pre soaking 30 min at 82°C provided adequate rehydration prior to 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.     

Phytate Reduction in Brown Beans (Phaseolus vulgaris L.)

Brown beans (Phaseolus vulgaris L.) were subjected to treatments to evaluate effects of pH, temperature, CaCl₂, tannase and fermentation on degradation of phytate. Soaking was performed at 21°C, 37°C and 55°C at pH 4.0, 6.0, 6.4, 7.0, and 8.0. Optimal conditions for phytate degradation were pH 7.0 and 55°C. After soaking 4, 8 or 17 hr at these conditions 79%, 87% and 98% of phytate was degraded, respectively. Addition of tannase enhanced reduction of phytate. Fermentation of presoaked whole beans resulted in reduction of 88% of phytate after 48 hr.     

Processing Factors Influencing Splitting and Other Quality Characteristics of Canned Kidney Beans

Single factor changes from a standard canning process indicated that significant reductions in splitting resulted from higher soak Ca concentrations, higher soak temperatures, higher brine Ca concentrations, and shorter cooking times. Splitting in canned kidney beans was markedly reduced by soaking beans before cooking at temperatures of 66–71°C in solutions containing 150–350 ppm CaCl₂. Treatments giving lower gain in weight during soaking led to less splitting. Lower splitting was associated with lower drained weight and firmer cooked beans.     

Influences of Soaking Temperature and Storage Conditions on Hardening of Soybeans (Glycine max) and Red Kidney Beans (Phaseolus vulgaris)

The influences of soaking treatment and storage conditions on the softening of cooked beans, namely, soybeans and red kidney beans, were investigated. It was revealed that the softening of fresh soybeans and fresh red kidney beans was suppressed during subsequent boiling after soaking treatment at 50 and 60 °C. Furthermore, in treated aged soybeans and red kidney beans that were subjected to storage at 30 °C/75% relative humidity for 6 mo and soaking treatment at 50 to 60 °C, the hardness during cooking was further amplified. This suggested that the mechanism of softening suppression differs depending on the influences of soaking and storage. Analysis of the pectin fraction in alcohol insoluble solid showed insolubilization of metal ions upon storage at high temperature and high humidity in both soybeans and red kidney beans, which suggests interaction between Ca ions and hemicellulose or cellulose as cell wall polysaccharides. The results of differential scanning calorimetry (DSC) showed that aged soybeans exhibited a shift in the thermal transition temperature of glycinin‐based protein to a higher temperature compared with fresh soybeans. From the results of DSC and scanning electron microscopy for aged red kidney beans, damaged starch is not conspicuous in the raw state after storage but is abundant upon soaking treatment. As for the influence of soaking at 60 °C, it can be suggested that its influence on cell wall crosslinking was large in soybeans and red kidney beans in both a fresh state and an aged state.     

Oxidation-Reduction Potentials of Canned Foods and Their Ability to Support Clostridium Botulinum Toxigenesis

Oxidation-reduction potentials (Eh) of canned foods ranged from -18 to -438 mV. Foods packed in glass had higher redox potentials than those packed in cans. Only 4 out of 26 products tested reached positive redox values after exposure to air for 24 hr at 4°C. Inoculated containers of mushrooms, whole corn, cream corn, asparagus, beef gravy, kidney beans, green beans, cream of mushroom soup, cheddar cheese soup, and lima beans supported toxin production by C. botulinum; potatoes and beets did not.     

Hard-to-Cook Phenomenon in Beans: Effects of Accelerated Storage on Water Absorption and Cooking Time

Black beans stored for 7–14 days at 41°C, 100% RH, required more cooking time than fresh beans and thus paralleled cooking time for beans stored forr more than 1 yr at room temperature. With corrections for solids lost during soaking, water absorption did not differ between fresh and stored beans. The rate of electrolyte leakage was greater from stored beans than from fresh samples, indicating that the cotyledon deteriorated during aging. Bean moisture content was found to be related to cooking time. In general, the higher the moisture content after soaking, the shorter the cooking time. However differences in cooking times between fresh and aged samples persisted regardless of bean moisture content.     

Canning Quality Evaluation of Pinto and Navy Beans

Thermal processing of pinto and navy beans at 121.1°C for 16 or 14 min in a still retort gave similar sterilization value (F_o= 10) as the processing at 115.6°C for 45 min. The 121.1°C/16 or 14 min process produced beans with greater firmness than the 115.6°C/45 min process. The addition of CaCl₂ and EDTA improved firmness and color of canned beans. Calcium chloride also reduced clumping and splitting of the canned beans. Sensory evaluation showed that the acceptability of canned beans was reduced when CaCl₂ was increased up to 10 mM. High correlation between firmness and soluble pectin in various bean cultivars implied that soluble pectin content could be used as a parameter for screening bean cultivars with desirable firmness.     

A cyclically pressurised soaking process for the hydration and aromatisation of cannellini beans

Hydrating beans before cooking reduces cooking time, increases their tenderness and weight and improves their appearance after cooking. In this paper, we describe a process of cyclically pressurised soaking for the rapid hydration of cannellini beans at room temperature. This hydration process is approximately ten-fold faster than the traditional soaking procedure, and the microbial load developed by the end of this process is much lower compared to that obtained using the traditional process. This bean hydration process was achieved with a new extraction technique using the Naviglio extractor, which subjected the water containing the beans to cycles of pressurisation in which the pressure values ranged between 0 (atmospheric pressure) and 10 bar. This innovative hydration process (I) reduced the time required for the complete hydration of the beans to approximately 60 min and produced a product saturated with the same final amount of moisture as the product obtained from the conventional soaking process (T) that lasts 12–20 h. The numerical simulation of the hydration process (I) has provided useful indications on how the diffusion of humidity inside the beans occurred during the pressurised soaking process. The treated beans were packaged, and organoleptic tests, including taster panel tests, were conducted. Finally, the aromatisation of the legumes was conducted in conjunction with the hydration process to introduce flavouring elements used in some famous traditional recipes for Italian cuisine.     

A Kinetic Interpretation of Textural Changes in Black Beans During Prolonged Storage

Control and roasted (80°C), dry black beans (Phaseolus vulgaris) were stored for 9 months at 8, 10, 12, and/or 14% moisture content and 8.5°, 25°, and 40°C. Similarly, beans heated in a solid-to-solid roaster to 51°, 61°, 72.3°, 80°, 85.5°, 89.5°, lO1°, and 111°C were maintained at 8% moisture and 25°C. Final hardness increased with moisture content and temperature. Hardening at 8.5° and 25°C proceeded initially almost linearly reaching a constant value after 4 to 6 months while at 40°C it was sigma-shaped. A pseudo-zero order kinetic model fitted for initial rates had an activation energy of 6–11.8 kcal/mol. The hardening rate at 25°C paralleled the shape of the sorption isotherm.     

Amino Acid Composition and Some Antinutritional Factors of Cooked Faba Beans (Medammis): Effects of Cooking Temperature and Time

Easy-and hard-to-cook bean seeds were cooked by different heat treatments (100–125°C for 1–12 hr). Amino acid composition, tannins, phytic acid and trypsin inhibitor activity were determined. Almost all essential amino acids declined after cooking. Less than 10% of total tannins were decomposed during cooking, while up to 50% were leached to the cooking liquor. Retention of phytic acid in cooked beans was significantly lower than in cooked bean-liquor mixtures. Loss of phytic acid due to leaching was much higher for easy-to-cook beans than for hard-to-cook ones. Apparent retention of trypsin inhibitor activity amounted to about 50%. Optimum heat treatments were 125°C at 1 hr for easy and 120°C at 2 hr for hard-to-cook beans.     

Effect of Temperature on the Serum Viscosity of Tomato Juice

Tomato juice was canned and exposed to processing temperatures of 82°C., 102°C and 112°C. Serum viscosity was measured after 30, 60, and 120 min at each temperature. Heat treatment affected serum viscosity. A temperature of 82°C applied for 2 hr resulted in a 17-30% loss of serum viscosity depending on the cultivar. Treatment at 112°C applied for 2 hr caused 67-82% loss, again depending on the cultivar.     

Effect of Pretreatment on the Cooking Time of the African Yam Bean (Sphenostylis sternocarpa)

The effect of soaking in tap water, 1% potash, and 4% sodium chloride for different periods on the cooking time of African Yam Bean was studied. The results showed that 12 hr soaking was adequate for the beans to reach maximum hydration, and that pretreatment of the beans before cooking appreciably influenced the overall cooking time. Cooking after pretreatment for 12 hr in 1% potash or in 4% sodium chloride reduced the normal cooking time by 50%.     

Physico-chemical characterization of stored black beans (Phaseolus vulgaris L.)

Selected physical and chemical characteristics were studied on black beans (Phaseolus vulgaris L.) after 2 years of storage under refrigerated hypobaric conditions (RHC) and ambient conditions (AC). Black beans stored under RHC of 4.5°C, 50–60% relative humidity and atmospheric pressure of 125 mm Hg exhibited quality factors characteristic of fresh beans, such as shorter cooking time, smaller quantities of solids loss, electrolytes leached, and percentage of hardshell than beans stored at AC of 23–25°C and 30–50% relative humidity. Additionally, beans stored under RHC demonstrated greater germination rate (93%) than beans stored at AC (72%). Beans stored at AC exhibited quality factors characteristic of hard-to-cook (HTC) beans. Percentage water absorption indicated a faster initial hydration rate in beans stored under RHC compared to beans stored at AC until after 12 h of soaking, when both reached a similar hydration rate. Moisture content of beans stored under RHC was similar to that of beans prior to storage, while the moisture content of beans stored at AC was significantly lower. Crude protein, crude fat, and ash concentration of beans prior to storage and beans stored for 2 years under RHC or AC were not significantly different. The electrophoretic profile of the main protein of beans, globulin G1, was not altered by the storage conditions. The combined effect of refrigeration and hypobaric storage conditions demonstrated potential for maintaining the fresh quality of beans in storage for up to 2 years.     

Water sorption and cooking time of red kidney beans (Phaseolus vulgaris L.): part I – Effect of freezing and drying conditions on water sorption and cooking time

Water sorption and cooking time of kidney beans were determined. The beans were manually harvested at 19.2 ± 0.1% moisture content and stored at ?20 and ?10 °C for about half a year. The beans were further dried at 30, 40 and 50 °C inside a thin‐layer drier for 7.5 h or under room conditions for 4 week. The freezing storage temperature before the beans were dried did not influence their cooking time and water sorption. The saturated kernel volumes decreased approximately 7% after drying. The beans decreased their sphericity during water sorption and had a larger swelling ratio in the thickness direction than in other directions. Lower initial moisture content, especially with a higher drying temperature, decreased water sorptivity and resulted in higher percentage of uncooked kernels if the beans were not soaked before cooking. However, there was no relationship between initial moisture content and uncooked percentage if the beans were soaked before cooking. High drying temperature resulted in hard‐to‐cook (HTC) phenomenon.     

Characteristics of soybeans as affected by soaking conditions

The water absorption of soybeans in soaking is directly related to the changes in textural characteristics and grinding properties of soybeans for processing. In this study, we determined the characteristics of water absorption, solid loss, and moisture content, textural characteristics and grinding properties of soybeans at four different soaking temperatures, 10°C, 20°C, 30°C, and 40°C, and various soaking times up to 8 h. We found that the solid loss increased significantly when the soaking temperature increased from 30°C to 40°C. The measured moisture data of soaked soybeans fitted well with the data predicted using Peleg's equation. Rupture force and maximum tangent and secant modulus measured by the compression test decreased as the moisture increased, up to 122%. The grinding property of soaked soybeans was related only to the final moisture content and not to the soaking conditions. High soaking temperature could significantly reduce the required soaking time. Based on these results, we recommend that soybeans be soaked to minimal final moisture content of 120% before grinding.     

Chemical and Physical Changes in Beet (Beta vulgaris L.) Root Tissue During Simulated Processing–Relevance to the "Black Ring" Defect in Canned Beets

Preheating slices of beet root tissue at 40 to 60°C led to a loss in tissue integrity indicated by higher leakage of electrolytes and endogenous pigments, and increases in water soluble pectin content. When tissue slices were incubated at 25°C for 1 hr after preheating at 50 to 60°C, reducing sugar increased. Incubation after preheating at 40 to 60°C resulted in decreased phenolic acid content. Endogenous poly-phenoloxidase and peroxidase retained about 50% of their original activity after preheating for 5 min at 70 and 60°C, respectively. These results bear relevance on the occurrence of the “black ring” defect in canned beets.