An assessment of the protein quality and vitamin b content of commonly used fermented products of legumes and millets

Fermented products of legumes, Bengal gram dhal (Cicer arietinum) and green gram dhal (Phaseolus aureus), and millets, bajra (Pennisetum typhoideum), jowar (Sorghum vulgare) and ragi (Eleucine coracana), were analysed for protein quality and vitamin B content. Fermentation reduced total crude protein by 6-8 % in the legume products and 4-6% in the millet products of bajra and ragi. No reduction in crude protein was observed in fermented jowar products. Temperature of batters increased considerably on fermentation, while pH decreased. The protein efficiency ratio (PER) and the true digestibility (TD) of legume products were not altered by fermentation, the biological value (BV) and net protein utilisation, (NPU), of Bengal gram dhokla improved significantly (P<0.05). The TD of fermented jowar increased significantly (P < 0.05) but not that of ragi, bajra and the legume products. BV and NPU of both jowar and ragi products increased significantly on fermentation (P<0.05) but not that of bajra. The thiamin and riboflavin contents of both the legume and millet products increased with increase in fermentation time. Steaming and cooking after fermentation reduced the thiamin and riboflavin content. However, fermentation after cooking of millet batters increased the levels of both vitamins markedly.     

Cooking does not impair the impact of pulsed electric field on the protein digestion of venison (Cervus elaphus) during in vitro gastrointestinal digestion

The present study was conducted to elucidate whether cooking impairs the positive effect of pulsed electric field (PEF) on the digestibility of venison during in vitro gastrointestinal protein digestion. Previous studies have used fresh uncooked meat to demonstrate the effect of PEF on protein digestibility during gastrointestinal digestion neglecting the effect that cooking could induce during meat preparation process. PEF-treated samples (T₁, 10 kV, 90 Hz, 20 µs) were cooked (core temperature of 75 °C) and subjected to in vitro simulated gastrointestinal protein digestion along with non-treated controls. A 3% increase of in vitro protein digestibility was found in cooked PEF-treated venison (P < 0.05). A positive (P < 0.05) impact of PEF processing was observed on overall protein digestion as measured by soluble protein (%) and SDS-PAGE. PEF did not change (P > 0.05) the release of minerals from cooked venison during digestion. Cooking had no negative influence on the mechanism through which PEF operates in improving the protein digestibility of venison.     

Sensory evaluation and in vitro protein digestibility of mung bean as affected by cooking time

Heat treatment is particularly important in the preparation of mung bean for consumption, from the point of view not only of acceptability but also of improvement on protein digestibility. Sensory evaluation of cooked mung bean in terms of taste, colour, aroma and texture has an organoleptic panel indicated that there was no significant difference (P < 0.05) between mung bean cooked for 25, 30, 35, 40 and 45 min. An in vitro protein digestibility assay was used to examine the effect of cooking time on protein digestibility. The applied non-linear mathematical model indicated a high correlation coefficient between experimental and predicted data (R² ≥ 0.999). A maximum improvement in in vitro protein digestibility (IVPD) of 4.83% was obtained by cooking for 38.6 min. No remarkable changes in most amino acids were found between raw and cooked samples except that tryptophan was decreased by 4.69% and a 10.29% loss of threonine occurred with the optimum cooking time. © 1999 Society of Chemical Industry     

Effect of rabadi fermentation on phytic acid and in vitro digestibility of barley

Rabadi, an indigenous fermented food, was prepared by mixing cereal flour with buttermilk, allowing it to ferment at 30, 35 and 40 °C for 6, 12, 18, 24 and 48 h and cooking the fermented mixture for 0.5 h with continuous stirring. Two types of rabadi were prepared i.e. autoclaved and unautoclaved. In autoclaved type of rabadi cereal flour was mixed with water, autoclaved (0.103 MPa = 15 psi for 15 min), cooled, mixed with buttermilk and fermented. As this type of rabadi was precooked prior to fermentation, hence, the fermented product did not require cooking afterwards, while in unautoclaved rabadi, barley flour and buttermilk were mixed, fermented and then cooked prior to consumption. Phytic acid was reduced drastically at all the temperatures and periods of fermentation in both autoclaved and unautoclaved type of rabadi; greater reduction occurred at higher temperature and duration of fermentation. A significant improvement in the in vitro digestibility of starch and protein was observed; maximum improvement was noticed when fermentation was carried out at 40 °C for 48 h in both the types of rabadi. Phytic acid had a significant (P < 0.05) negative correlation with digestibility (in vitro) of proteins and starch of barley flour rabadi.     

Proximate compositions, pasting and rheological properties of mumu– a roasted maize meal

Genetically improved maize variety (TZRS‐W) grains were used to produce mumu– a roasted maize meal. The grains were divided into six treatment groups namely: non‐soaked, non‐cooked (NSNC); non‐soaked, cooked (NSC); soaked, non‐cooked (SNC); soaked, cooked (SC); germinated non‐cooked (GNC); and germinated, cooked (GC). Each group was roasted in the oven at 150 °C for 1 h to produce mumu. No significant differences (P ≤ 0.05) were found in the protein, fat, ash, fibre and carbohydrate contents of the different products. Soaking and germination without cooking resulted in lower breakdown viscosities of the products. The peak viscosity (20.17 Rapid Visco Unit (RVU)) and final viscosity (28 RVU) of the GNC samples were significantly higher (P ≤ 0.05) than the corresponding values (5.17–7.25 RVU) of the NSNC, NSC, SNC, SC and GC products. No significant differences (P ≤ 0.05) were found in the pasting temperatures (63.40–64.85 °C) between all the six groups. Germination for 24 h without cooking may yield poor quality products with low nutrient density.     

In vitro digestibility of processed and fermented soya bean,cowpea and maize

Tropical legumes, ie soya bean and cowpea, were pre‐treated and subsequently fermented using pure cultures of Rhizopus spp. Impact of soaking, cooking and fermentation of the legumes on their digestibility was determined using an in vitro digestion method. Processing of white maize included, amongst others, natural lactic acid fermentation, cooking and saccharification using barley malt. An in vitro method was standardised to carry out comparative determinations of the dry matter digestibility of cereal and legume food samples as a function of processing conditions, without attempting to exactly mimic gastrointestinal digestion. Using this method based on upper digestive tract digestion, it was observed that digestibility of the legumes increased during cooking and fermentation. Cooking improved the total digestibility of both soya bean and cowpea from 36.5 to 44.8% and from 15.4 to 40.9% respectively. Subsequent fungal fermentation increased total digestibility only by about 3% for both soya bean and cowpea. Digestibility was also influenced by fungal strain and fermentation time. Cooking and subsequent saccharification using malt almost tripled total digestibility of white maize from 25.5 to 63.6%, whereas lactic fermentation of maize had no effect on in vitro dry matter digestibility. Although total digestibility of cooked legumes was only slightly improved by mould fermentation (3% for both soya bean and cowpea), the level of water‐soluble dry matter of food samples increased during fermentation with Rhizopus oryzae from 7.0 up to 27.3% for soya bean and from 4.3 up to 24.1% for cowpea. These fermented products could therefore play a role as sources of easily available nutrients for individuals suffering from digestive disorders. © 2000 Society of Chemical Industry     

Physical and Chemical Attributes of a Ready-to-Eat Meat Product during the Processing: Effects of Different Cooking Methods

The effects of cooking time (10–50 min) and treatments (atmospheric, pressure, and microwave cooking) on Kavurma (a ready-to-eat meat product) were investigated. Atmospheric and pressure cooking technique had more desirable quality attributes than microwave cooking technique on kavurma production. Color, texture, moisture content, pH, and 2-thiobarbituric acid reactive substance values were followed during processing. Moisture content, pH, 2-thiobarbituric acid reactive substance, hardness, and chewiness values of microwave cooked samples were significantly different (p < 0.05) than that of atmospheric and pressure cooked samples. The microwave cooking method had the greatest influence on lipid oxidation compared to others. While the level of 2-thiobarbituric acid reactive substance was lower which was under the threshold value of 1 mg MA/kg in atmospheric and pressure cooking, it was higher in microwave cooking. On the other hand, among Hunter color values, lightness value increased (p < 0.05) for atmospheric cooked samples while it decreased by time for pressure and microwave cooked samples. However, a* and b* values of microwave and pressure cooked samples were significantly higher than atmospheric cooked samples.     

Oligosaccharides, Antinutritional Factors, and Protein Digestibility of Dry Beans as Affected by Processing

Dry beans (Phaseolus vulgaris) were subjected to soaking, cooking or a combination of both prior to fermentation, and then assessed for oligosaccharides, antinutritional factors and in-vitro protein digestibility. Results showed an important decrease in raffinose oligosaccharides and antinutritional factors. However, an increase of trypsin inhibitor and tannin contents occurred respectively in cooked or soaked-cooked fermented beans and in raw or soaked fermented beans. Appreciable improvement in in-vitro protein digestibility was only observed in cooked or soaked-cooked beans. After fermentation, the largest decreases were observed in soaked-cooked beans (92.75%) for raffinose, in cooked beans (31.57%) for phytic acid, in soaked beans (90.86%) for stachyose, and in raw beans for trypsin inhibitor (38.77%). The highest increase due to fermentation was observed in raw beans for in-vitro protein digestibility (1.73%).     

Effects of different cooking methods on the mineral contents of wild and farmed sea bream (Sparus aurata)

The effects of different cooking methods (steaming, boiling, oven cooking, grilling, frying in olive oil, frying in soybean oil, frying in corn oil and frying in sunflower oil) on mineral contents (Ca, Mg, K, Na, Fe, Zn, Cu and Mn) of wild and farmed sea bream (Sparus aurata) were determined. The moisture rate decreased significantly (P < 0.05) after boiling, grilling, oven cooking and frying but remains stable after steaming. The fat content increased with different frying treatments. The Ca, Mg, Na, K and Zn contents of wild and farmed sea bream cooked by almost all methods significantly decreased (P < 0.05). The Cu content in grilled wild and farmed sea bream increased significantly (P < 0.05). Losses of mineral content in fried sea bream were higher than those of fish cooked by other methods. On comparing the raw and cooked fish, the results indicated that cooking had considerable effect on the mineral contents.     

Nutritional value of African yambean (Sphenostylis stenocarpa,L): improvement by solid substrate fermentation using the tempeh fungus Rhizopus oligosporus

The tropical African yambean (AYB, Sphenostylis stenocarpa L.) is a hardy, protein‐rich under‐utilised African legume. Anti‐nutrients, and the excessively long cooking time (4–6 h), among other factors, limit the food use of African yambean seeds. To reduce these limitations, non‐traditional, less energy consuming processing methods are required. Seeds of different varieties were (1) examined for proximate composition and (2) fermented with Rhizopus oligosporus for the production of tempeh. The traditional production process involves dehulling, soaking in water for 24 h, boiling in water for 30 min, inoculation and fermentation. In addition, the traditional procedure for preparing tempeh was modified by using 1% citric acid solution instead of water for soaking and cooking. Comparisons with traditionally cooked beans, which involved boiling in water for 4 h, were made. The traditional tempeh procedure resulted in a slight but significant increase in protein and starch (P < 0.05) and an almost complete loss of most of the anti‐nutrients of AYB seeds, although the cyanogenic glycoside content of AYB‐white remained high. The modified procedure resulted in a bacteria‐free tempeh and the cyanogenic glycosides were no longer detectable. In vitro protein digestibility of the 1% citric acid treated sample was slightly lower than that of the water‐treated sample. Both tempeh production processes were clearly more effective and less energy intensive than traditional cooking in improving nutritional quality, but only the modified method of tempeh production eliminated the possibility of cyanide poisoning. Copyright © 2006 Society of Chemical Industry     

Proximate composition and digestibility of fermented and extruded uji from maize-finger millet blend

The proximate composition, amino acid profile and in vitro starch and protein digestibilities of raw; fermented; fermented and cooked; unfermented and extruded; and fermented and extruded maize-finger millet blend was studied. Aspartic acid, glycine, cystine, methionine, tyrosine and lysine increased after fermentation, while contents of all other amino acids showed no significant changes. Greater losses of amino acids occurred when the fermented blend was extruded than when cooked. Fermentation improved protein and starch digestibilities, whereas cooking or extruding the fermented blend reduced the digestibilities. Extruding the unfermented blend increased protein and starch digestibilities and reduced nitrogen solubility index by 50%. Raw flour had 0.41 g/100 g water-soluble starch which declined to 0.05 g/100 g on fermentation but increased to 20-34 g/100 g after extrusion.     

Structural changes of meat protein of chicken sausages with various levels of salt and phosphate and their effects on in vitro digestion

The objectives of this study were to evaluate protein oxidation and in vitro digestibility of chicken sausages with various salt/phosphate combinations. Hydrophobicity increased when protein was cooked and denatured (P < 0.05). Protein oxidation was increased based on levels of SH, S-S and carbonyl groups during the cooking process (P < 0.05). Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) revealed that the intensity of myosin heavy chain band was decreased while biopolymer band was denser when sausages were cooked. Sausages with 1.8% salt and 0.3% phosphate (S1P1) showed the lowest digestibility and maintained a flat and compact structure, unlike other treatments during the gastrointestinal digestive stage. SDS-PAGE of digested chicken sausages showed that protein bands were degraded into small bands followed by gradual disappearance. In conclusion, cooking process can lead to protein denaturation and oxidation, regardless of levels of salt and phosphate added. In addition, adding salt and phosphate can significantly affect the digestibility of meat products.     

Use of rosemary and Hibiscus sabdariffa in production of kavurma,a cooked meat product

BACKGROUND: Spices are used in different types of foods to improve flavours and are well known for their antioxidant properties. The objective of this study was to determine the effects of rosemary and Hibiscus sabdariffa on the quality attributes of kavurma, a cooked meat product. RESULTS: pH values of samples remained constant (P > 0.05) at about 6.35 during the cooking period, and addition of H. sabdariffa, rosemary or butylated hydroxytoluene (BHT) did not significantly affect pH values (P > 0.05). However, addition of antioxidants decreased (P < 0.05) thiobarbituric acid‐reactive substance (TBARS) values, the highest values being observed in control samples. Lightness (Hunter L) values of control samples increased (P < 0.05) from 28.79 to 37.91 during the first 20 min of cooking. Hunter a and b values were significantly affected (P < 0.05) by process time and addition of antioxidants. Addition of BHT, rosemary or H. sabdariffa did not affect the overall sensory attributes of kavurma during the cooking process. CONCLUSION: Colour values changed during the cooking process, mainly as a result of browning reactions. Addition of rosemary or H. sabdariffa enhanced the colour attributes of kavurma during cooking. Rosemary and H. sabdariffa could be used to modify the quality characteristics and obtain kavurma with a low TBARS value and probably a longer shelf‐life. Copyright © 2009 Society of Chemical Industry     

Characterization of fermented black soybean natto inoculated with Bacillus natto during fermentation

BACKGROUND: To make nutrients more accessible and further increase biological activity, cooked black soybeans were inoculatedwith Bacillus natto and fermented at 37 °C for 48 h. The changes in physiochemical properties of fermented black soybean natto were investigated. RESULTS: The inoculation procedure significantly increased moisture, viscosity, color, polyphenol compounds and anthocyanin, and significantly decreased hardness after 48 h fermentation. Fibrinolytic and caseinolytic protease, β‐glucosidase activities, TCA‐soluble nitrogen, and ammonia nitrogen contents in the inoculated samples significantly increased as fermentation time increased. Genistin and daidzin concentrations gradually decreased with increased fermentation time. However, genistein and daidzein increased with fermentation time, which reached 316.8 and 305.2 µg g^?1 during 48 h fermentation, respectively. DPPH radical scavenging activities of the fermented black soybeans increased linearly with fermentation time and concentration. Compared with the soaked black soybeans and cooked black soybeans, the fermented black soybeans with B. natto resulted in higher scavenging activity towards DPPH radicals, which correlated well with the content of total phenols (r = 0.9254, P < 0.05) and aglycone isoflavone (r = 0.9861, P < 0.05). CONCLUSION: Black soybean natto fermented by B. natto has the potential to become a functional food because of its high antioxidant activity. Copyright © 2010 Society of Chemical Industry     

The influence of tempeh fermentation and conventional cooking on anti‐nutrient level and protein bioavailability (in vitro test) of grass‐pea seeds

BACKGROUND: The solid state fermentation tempeh type is known to result in the decomposition of anti‐nutrients and the improvement of nutritional value of legume seeds. The aim of the research was to study the influence of tempeh fermentation and conventional cooking on (1) levels of 3‐N‐oxalyl‐L ‐2,3‐diaminopropionic acid (ODAP), soluble phenols, trypsin inhibitors and inositol phosphates; and (2) the in vitro bioavailability of proteins in grass‐pea seeds. RESULTS: Tempeh fermentation reduced the level of ODAP, trypsin inhibitors and phytates by 93, 99 and 22%, respectively, and increased protein bioavailability by about 25%. Protein bioavailability from conventionally cooked seeds was higher than from fermented seeds. However, during the in vitro test more soluble protein (approx. 10%) was released from 100 g tempeh product than from cooked seeds. CONCLUSIONS: Solid state fermentation and cooking resulted in seeds of comparable quality but the tempeh contained much less ODAP, which is very promising in the context of popularising grass pea. Copyright © 2008 Society of Chemical Industry     

L‐Carnitine Contents in Seafoods Commonly Eaten in Middle Eastern Countries

Beta‐hydroxy‐gamma‐trimethyl amino butyric acid (L‐carnitine) content of raw and cooked seafood was determined using high‐performance liquid chromatography method. Thirty‐one different fish species and nine different crustaceans were used to compare L‐carnitine content of raw and cooked seafood. Significant differences in L‐carnitine content were found in some species, regardless of the raw or cooked seafood (P < 0.05). There were also significant differences between some of the raw and cooked species (P < 0.05). The levels of L‐carnitine in raw fish samples ranged from 17.98 mg/kg for big‐scale sand smelt to 73.07 mg/kg for European conger (Conger conger). Squid (Loligo vulgaris) and green tiger prawn (Penaeus semisulcatus) were found as the best sources of L‐carnitine among the tested seafood. Microwave cooking also significantly reduced the L‐carnitine content of some seafoods (P < 0.05). The study showed that seafoods are an important origin of L‐carnitine for covering the daily requirements of humans.     

Nutritional value of African yambean (Sphenostylis stenocarpa L): improvement by lactic acid fermentation

Tropical African yambean (Sphenostylis stenocarpa L) is an under‐utilised hardy, protein‐rich legume. Antinutrients and the excessively long cooking time (4–6 h), among other factors, limit the food use of African yambean seeds. To reduce these limitations, non‐traditional, less energy‐consuming processing methods are required. Seeds of different varieties were (i) examined for ingredients and (ii) fermented with Lactobacillus plantarum. Comparisons with traditionally cooked beans were made. Protein content and in vitro protein digestibility were increased slightly by fermentation or cooking. Reductions in trypsin and α‐amylase inhibitor activity and tannin ranged from significant to complete. The contents of potentially very toxic cyanogenic glycosides and flatulence‐causing α‐galactosides were high in raw beans. Reduction by fermentation (by 85%) was clearly more effective than by traditional cooking (10–20%). The results demonstrate (i) that fermentation can substantially improve the nutritional quality and (ii) that the energy requirement to produce a basic consumable fermented food from African yambean is only 10% of that of traditional cooking. On these grounds, widespread application of lactic acid fermentation by individuals or small‐scale industries would be advantageous in the context of small‐household economy, environmental protection, health and long‐term sustainable agriculture in Nigeria. Copyright © 2005 Society of Chemical Industry     

Lipid characteristics in cooked, chill-reheated fillets of Indo-Pacific king mackerel (Scomberomorous guttatus)

Slices of Scomberomorous guttatus cooked by four different methods (microwave cooking, grilling, steaming and shallow fat frying) were kept chilled at 5 °C for 2 days, reheated by microwave and then evaluated for the changes in the lipid characteristics. The total lipid content for raw sample was 6.0 g/100 g which consist of 49.4 g/100 g saturated (SFA), 6.9 g/100 g monounsaturated (MUFA) and 43.8 g/100 g polyunsaturated fatty acids (PUFA). Upon cooking, the total lipids changed to about 7 (microwave), 11 (grilling), 5 (steaming) and 10 g/100 g (shallow fat frying). These changes are significant, with the exception of steam cooking. Cooking did not significantly affect the percentage of NPL, PL, SFA, MUFA and PUFA in the samples. Frying resulted in the change of the SFA/PUFA ratio more than other cooking methods. A significant (P < 0.05) decrease in the content of EPA was only found in the fried samples. A significant (P < 0.05) decrease in the content of DHA in all cooked samples were also obtained. The n-6/n-3 ratio did not change significantly in all cooked and reheated samples, except for shallow fat fried. Reheating did not significantly affect the NPL and PL contents of the fillets, except for microwave cooked samples. Cooking increases the FFA, PV and TBA of samples; reheating enhances the increase.     

The sensory quality of dry fermented sausages as affected by fermentation stage and curing agents

The effects on the quality of dry fermented sausages of applying either a slow or rapid fermentation stage, and the addition of either nitrate or nitrite was studied. In the slow fermentation process, TBARS were higher in the batch made with nitrite than in the batch containing nitrate. For rapid fermentation, both batches, with added nitrate and nitrite, presented intermediate TBARS levels. Volatile compounds coming from lipid oxidation and microbial lipid β-oxidation were more abundant (p < 0.05) in the samples submitted to a rapid fermentation stage, whilst compounds coming from amino acid catabolism and carbohydrate fermentation were higher (p < 0.05) in samples subjected to a slow fermentation stage. A significant preference (p < 0.05) was shown during sensory analysis for the batch made with nitrate and submitted to the slow fermentation process in aroma, taste and overall quality, whilst no differences in sensory analysis were detected among batches in the rapid fermentation process. Therefore, the use of nitrate is only justified in slow fermented processes due to its positive effect on the sensory quality of fermented sausages.     

Quality Evaluation of an Ohmically Cooked Ham Product

Selected parameters (cooking loss, instrumental colour and texture and sensory quality) of a brine-injected pork muscle cooked by a novel and rapid ohmic cooking protocol were examined and compared with those obtained in conventionally cooked samples. Ohmic samples were cooked using either a low-temperature long-time (LTLT) protocol (2 min equilibration, 5 min ohmic heating to 70 °C, 8 min holding) or a high-temperature short-time (HTST) procedure (2 min equilibration, 6 min ohmic heating to 95 °C) performed within a hot air cabinet set at 80 °C (LTLT) and 100 °C (HTST). Conventional cooking (steam oven at 80 °C for 120 min) was conducted to a core temperature of 70 °C. The LTLT treatment gave a much lower cooking loss value (4–5% lower, p < 0.05) than the other treatments, though the full magnitude of this difference was not completely reflected in the proximate composition of the cooked products. Ohmically cooked ham showed a significantly (p < 0.05) lighter surface colour with Hunter L values of 65.3 (LTLT) and 63.5 (HTST) relative to the control (61.4). Texture profile analysis (TPA) indicated a significant difference (p < 0.05) in hardness (N) especially between the HTST surface (82.1 N) and the conventional centre (58.8 N). Although the ohmic cooking protocols yielded products with quite acceptable eating qualities, sensory evaluation found the overall quality of the conventionally cooked ham to be significantly (p < 0.05) superior, indicating that further optimisation of the ohmic cooking protocols would be required prior to any commercial adoption.