Innovative Cooking Techniques for Improving the Overall Quality of a Kailan-Hybrid Broccoli

The microbial, physical, sensory and nutritional quality of boiled (vacuum and conventional), steamed, pressure cooked, sous vide, microwaved (sous vide and conventional), deep-fried (vacuum and conventional) and grilled kailan-hybrid broccoli (Bimi®) after cooking was studied. Sous vide microwaving greatly decreased microbial counts, achieving very low psychrophilic and enterobacteria counts (1.1 and 0.2 log CFU g^?1, respectively). Vacuum boiling and sous vide reduced the stem broccoli firmness by approximately 54–58 %, reaching a pleasant and moderate softening. Sous vide, grilling and steaming induced the lowest stem colour changes. Generally, all cooking treatments showed a good overall sensory quality. The total phenolic content (1,148 mg CAE kg^?1 fw) usually increased after cooking, with microwave and grilled treatments registering the highest increases up to 2-fold. Commonly, the total antioxidant capacity (296.6 mg AAE kg^?1 fw) increased after cooking by sous vide, microwaving and frying treatments registering the highest increments, by approximately 3.6-fold. Generally, the cooking process reduced the initial vitamin C content, with vacuum and conventional boiling showing the lowest and highest losses with 27 and 62 %, respectively, while vacuum deep frying preserved the initial value (1,737 mg kg^?1 fw). As a main conclusion, the studied grilling and vacuum-based cooking treatments resulted in better microbial quality, colour, stem firmness and sensory quality than the remaining ones. This maintained or even improved the total antioxidant content of the new kailan-hybrid broccoli studied.     

Induced changes in bioactive compounds of kailan-hybrid broccoli after innovative processing and storage

The glucosinolates, sulforaphane, vitamin C and lutein content after several industrial cooking methods on the new kailan-hybrid broccoli and their changes during storage for 45 days at 4 °C were studied. Boiling and sous vide induced the highest glucosinolate loss (80%), while low pressure (LP) steaming, microwaving (MW) and sous vide-MW showed the lowest (40%) loss. Glucoraphanin was the most thermostable glucosinolate. Throughout their commercial life, microwaved and grilled samples showed a decrease in total glucosinolates. Generally, myrosinase activity was completely inhibited after cooking with undetected sulforaphane contents. The initial total vitamin C dropped by up to 58% after cooking and progressively decreased during storage, with sous vide-MW (92%) and microwaving (21%) showing the highest and lowest decrements, respectively. LP steaming and microwaving were the best industrial cooking methods for maintaining the glucosinolate and vitamin C contents, and enhancing up to 7.5-fold the initial lutein content.     

Effect of sous vide cooking, with freezing, on selected quality parameters of seven fish species in a range of sauces

As quotas and the supply of conventional species continue to tighten, there is a need to test the acceptability of many fish species. Seven fish species (albacore tuna, cardinal fish, orange roughy, blue ling, redfish, roundnose grenadier and Greenland halibut) were cooked by the sous vide process (Barriquand Steriflow retort; 20 min/90 °C) in 12 savoury sauces. Sensory results showed that sous-vide-cooked albacore tuna, cardinal fish and blue ling were the most acceptable species and tikka, tomato-and-pesto, arrabbiata and hollandaise the preferred sauces. Greenland halibut and roundnose grenadier were too soft after sous vide cooking. Freezing post sous vide cooking did not influence product quality and gave additional benefits over chilling of an extended shelf life and more flexibility in relation to product safety. The pH of the sauces was in the range 3.96 (cajun) to 5.42 (bearnaise) and mean pH values fell from 4.66 before sous vide cooking to 4.38 after cooking. Sauce colour also became lighter during sous vide cooking of fish portions, as indicated by Hunter Lab colour values. The results of the research have been disseminated to seafood companies and scale-up trials are in progress.     

Vitamin C,total phenolics and antioxidative activity in tip‐cut green beans (Phaseolus vulgaris) and swede rods (Brassica napus var. napobrassica) processed by methods used in catering

BACKGROUND: Retention of nutrients in vegetables during blanching/freezing, cooking and warm‐holding is crucial in the preparation of both standard and therapeutic diets. In the present study, conventional cooking in water, and cooking by pouch technology (boil‐in‐bag, sous vide) were compared in their ability to retain vitamin C, total phenolics and antioxidative activity (DPPH and FRAP) in industrially blanched/frozen tip‐cut green beans and swede rods. RESULTS: After conventional cooking, 50.4% total ascorbic acid, 76.7% total phenolics, 55.7% DPPH and 59.0% FRAP were recovered in the drained beans. After boil‐in‐bag cooking, significantly (P < 0.05) higher recoveries were obtained, i.e. 80.5% total ascorbic acid, 89.2% total phenolics, 94.8% DPPH and 92.9% FRAP. Recoveries after sous vide cooking were comparable to those of boil‐in‐bag cooking. By conventional cooking, 13.5–42.8% of the nutrients leaked into the cooking water; by sous vide about 10% leaked to the exuded liquid, while no leakage occurred by boil‐in‐bag cooking. Warm‐holding beans after cooking reduced recoveries in all components. Recoveries in swede rods were comparable but overall slightly lower. CONCLUSION: Industrially blanched/frozen vegetables should preferably be cooked by pouch technology, rather than conventional cooking in water. Including cooking water or exuded liquid into the final dish will increase the level of nutrients in a meal. Warm‐holding of vegetables after cooking should be avoided. Copyright © 2010 Society of Chemical Industry     

Effects of modified atmosphere packing over the shelf life of sous vide from captive pirarucu (Arapaima gigas)

The goal of this study was to evaluate the effects of modified atmosphere in packing sous vide of pirarucu in tucupi and shrimp sauce under refrigeration. Three treatments were carried out vacuum at 98%, 60%CO₂/40%N₂, and 70%CO₂/30%N₂. The composition of CO₂ and N₂ was monitored along with evaluation of pH, a_w, water retention capacity, acidity, texture, N-TVB and TBARS, color, mesophilic and psychotropic anaerobes, presence of Salmonella spp, sulphite-reducing Clostridia, counts of coagulase-positive Staphylococci, coliforms at 45 °C and sensorial analysis. All results were compared through ANOVA, Tukey's test, Principal Component Analysis and Multiple Factor Analysis. We observed a trend towards the reduction of CO₂ in packages while O₂ has increased by the end of storage. The microbiological results were within the established limits by law during the entire period. The shelf life of sous vide stored could be defined by N-TVB, TBARS, b* and C*, general acceptance, texture and flavor in 49 days of storage.Industrial relevanceThe development of sous vide with freshwater fish is an alternative for a value-added product to be supplied to market niches. Employing the sous vide technique on fish yields a product with better color, taste, texture, and nutrient retention than the traditional cooking processes, which makes it an attractive alternative for its consumption. This study aimed to prepare sous vide using captive pirarucu, tucupi and shrimp and to analyze the microbiological, physicochemical and sensory quality parameters during refrigerated in atmosphere modified packaging storage. The results of this study establish the product's shelf life (49 days) and contribute to defining processing and storage conditions for fish sous vide.     

Vitamin fortified rice grain using spraying and soaking methods

The objective of this work was to fortify three types of rice grains (brown, white milled and parboiled) with B complex vitamins (B₁, B₂, B₃, B₅, B₆, B₁₂), using two different physical treatment methods, (1) soaking of whole dehusked or milled rice kernels in vitamin solutions at 90 °C for 15 min and (2) full spraying of whole kernels with vitamin solution at 35 °C, both followed by oven drying. Various nutrient concentrations were added and the vitamin retention of dried fortified as well as of cooked rice were determined. Fortified rice was evaluated based on vitamin retention, estimated as the percentage of vitamin in rice after fortification treatment versus the total amount of added plus its initially vitamin quantity. It was found that the average retention of all vitamins in dried rice was high and varied from 54.3% to 85.3% for the spraying and from 53.5% to 76.2% for the soaking method respectively. After rice cooking, the retention was maintained in sufficient level (>70%) for all vitamins except for B₁₂. When excess of water was used for cooking, the water-soluble vitamins were leached; however a significant amount of vitamins still remained, varying from 13.5% (B₁₂) to 51.2% (B₁). The good retention of vitamins, even after cooking, achieved applying these relatively simple techniques, may be attributed to the absorption and diffusion of vitamins in the interior of rice kernels in high concentrations. Dried fortified rice samples properties were evaluated.     

The effect of cooking methods on mineral and vitamin contents of African catfish

Proximate composition, mineral and vitamin contents (A, E, B₁, B₂, niacin and B₆) were investigated in cooked African catfish. Different cooking treatments were used (baking, grilling, microwaving and frying). The protein and ash contents increased in all cooked fish. The fat content increased only in fried fillets. The moisture content of cooked fish decreased. Mineral levels were affected by cooking methods, except for Cu Although the vitamin A content significantly increased in grilled and fried fish, vitamin E increased in all cooked fish. Vitamin B₁ content of cooked fish significantly decreased. Vitamin B₂ and niacin contents of grilled fish increased significantly. B₆ content of cooked fish significantly decreased but this did not occur for the grilled fish. High levels of vitamin and mineral contents were found in grilled catfish.     

SELENIUM AND TOCOPHEROL CONTENT OF COOKED PORK ROASTS1

The content and the retention of the antioxidant nutrients, selenium and tocopherol (vitamin E), in boneless Chef's Prime^TM pork loin roasts cooked by different methods to 71 and 82C internal temperatures were determined. Roasts were cooked at 163C by roasting, braising, and in an oven cooking bag. Yield, moisture, and crude fat measurements were similar for all treatments. The only form of vitamin E in the sample was α-tocopherol. Selenium and vitamin E content as well as true retention values were similar in pork cooked to the two internal temperatures by the three household methods with one exception; the selenium content was significantly higher in pork cooked in the bag and roasted than in those prepared by braising. Overall, the selenium and vitamin E content of the cooked pork was 101.8 ± 0.5 μg/100g (X?± SEM) and 0.144 ± 0.006 mg α-TE/100g, respectively. Over half of the vitamin E but little to none of the selenium in the pork was lost during these household cooking procedures.     

The effect of freezing compared with chilling on selected physico-chemical and sensory properties of sous vide cooked carrots

Sous vide is increasingly used to process convenience foods including ready-meals as it is reputed to give superior quality because of the mild process and the absence of oxygen in the pack. The potential for temperature abuse is greater for sous vide ready-meals than for sous vide catered items as the distribution and retailing chain for the former is usually longer. Freezing sous vide foods is, therefore, a potentially safer alternative to sous vide processed foods followed by chilling. The objective of the current study was to investigate production of sous vide frozen sliced (discs) carrots, with similar quality to sous vide chilled product. Sensory trials were used to determine the acceptable shear texture range (1.0–2.8 kN) for steamed carrots and this was the target texture in the processing trials. A Barriquand Steriflow retort was used for sous vide processing and the optimized conditions using carrot discs were: low temperature blanch (50 °C/30 min; firms product); blanch (90 °C/3 min; inactivates enzymes); sous vide cook (90 °C to core P₉₀¹⁰ values > 4 min and < 6 min); blast freeze (? 35 °C/2 h); and store (? 25 °C). Carrot discs prepared from untreated raw carrots had a firmer texture than those prepared from either blanched or blanched and frozen material. Freezing post-sous vide cooking softened texture in comparison with chilling, but freezing rate (nitrogen; blast; cabinet methods) and frozen storage (9 months) had a minimal effect on product texture and quality. Scanning electron microscopy showed no significant structural differences between sous vide frozen and chilled carrots of similar shear values. Paired comparison sensory testing of sous vide frozen and chilled sliced carrots indicated a significant preference for the latter at the 20-day storage date.Industrial relevance: The trials dealt with the effects of freezing on the quality of sous vide processed carrots. This is of relevance to companies who wish to produce texturally acceptable sous vide frozen or chilled components as part of ready-meals.     

Amino Acid and Vitamin Composition of Raw and Cooked Horse Mackerel

Amino acid, vitamin (A, E, B₁, B₂, B₃ and B₆), and proximate composition were determined in raw and cooked horse mackerel. The changes in amino acid, vitamin, and proximate content were found to be significant for all cooking methods (frying, grilling, and steaming). Cooking did in general significantly increase the contents of essential, semi-essential, and other amino acids compared to raw fish species. Amino acid contents of grilled mackerel were significantly higher (p < 0.05) than those found in fried and steamed mackerel. The A, E, B₂, and B₆ vitamin content of fried horse mackerel was found to be significantly (p < 0.05) higher than the grilled and steamed samples. The B₁ content of steamed and B₃ content of grilled were found higher than the other cooked samples. Moisture, protein, fat, ash, and carbohydrate contents of cooked fish ranged between 56.52% to 61.34%, 20.79% and 23.93%, 13.44% and 19.61%, 1.70% and 2.47%, and 1.02% and 4.36 %, respectively. Fried fish had intermediate fat values, while grilled and steamed fishes had a comparatively low value.     

Ascorbic Acid and 5-Methyltetrahyclrofolate Losses in Vegetables with Cook/Chill or Cook/Hot-Hold Foodservice Systems

The percent retention of vitamin C and 5-methyltetrahydrofolate in seven cooked vegetables was analyzed using HPLC and compared in simulated cook/chill vs cook/hot-hold hospital foodservices. Retention of vitamins after conduction and infra-red reheating was investigated. Vegetables reheated after one day of chilled storage had greater losses of both vitamins compared to those held at 72°C for 30 min, but better vitamin retention than vegetables held hot 2 hr. There was no significant difference in nutrient retention due to method of reheating. If warm-holding is restricted to < 90 min, vitamin retention in vegetables is likely to be higher in a cook/hot-hold foodservice than with a cook/chill system.     

Palatability and Storage Characteristics of Precooked Beef Roasts

The palatability and storage characteristics of fresh, frozen and precooked beef chuck roasts prepared using added phosphate-salt and vacuum cooking bags were evaluated. Palatability attributes (tenderness, juiciness, beef flavor intensity, and off-flavor intensity) of precooked roasts prepared in vacuum cooking bags with phosphate-salt were as good or better than freshly cooked roasts. Precooked roasts in vacuum cooking bags had the lowest total bacterial counts after storage for 14 and 28 days. A palatable precooked roast beef product was developed that can be stored for 28 days at 4°C.     

<Emphasis Type="Italic">Sous</Emphasis><Emphasis Type="Italic">Vide</Emphasis> Processing as an Alternative to Common Cooking Treatments: Impact on the Starch Profile,Color, and Shear Force of Potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.)

This study aimed to assess the effect of sous vide cooking on the total and resistant starch content, color, and shear force in three potato cultivars (Agria, Agata, and Carrera). Potato strips were also cooked by three common treatments (boiling, frying, and microwaving) to evaluate the differences between the methods. According to principal component analysis (PCA), sous vide-processed cv. Agria and Agata potato strips were grouped with boiled samples, in contrast, cv. Carrera sous vide samples were grouped with microwaved samples. Higher water losses were associated with microwaved potatoes due to the diffusion of water inside the tuber. In addition, a significant decrease in shear force was obtained after microwaving and sous vide cooking (p < 0.05) irrespective of the treatment strength. The three cultivars became less bright, and the intensity of the color decreased; however, variations in the cook value (C ₁₀₀, min) between treatments did not affect the lightness and hue angle. Regardless of the initial value of resistant starch and the intensity of the cooking process, all of the cultivars reached a final content of less than 5%. From our results, in-pack sterilization may be considered for application in the food industry as a technology that has a similar impact to conventional cooking treatments used on potato products.     

Consumer and Trained Sensory Comparisons of Cooked Beef Top Rounds Treated with Sodium Lactate

Addition of 3% sodium lactate to beef top rounds increased cooking yields. Raw and cooked lactate-treated roasts were lower in moisture, but fat content was not affected. Aerobic plate counts at 42 and 84 days storage were lower in treated roasts than in controls, with hetero-and homofermentative Lactobacillus spp. constituting a dominant (>50%) part of the microflora at 84 days storage. Trained panel evaluations revealed that positive fresh flavor notes were enhanced, while warmed-over flavor notes and microbial spoilage were minimized by sodium lactate. Flavor profiles did not change during storage. Consumer panelists described treated roasts as flavorful with stronger beefy, meaty flavor, than control samples which were bland with weak beefy flavor.     

Clostridium sporogenes and Listeria monocytogenes: Survival and Inhibition in Microwave-ready Beef Roasts Containing Selected Antimicrobials

Beef roasts were pumped with brines containing phosphates and acetic acid, sodium lactate, potassium sorbate, or glycerol monolaurin, and cooked in-the-bag once or twice to 62.8°C. Samples were examined during storage at 2, 5, and 10°C and after mishandling at 25°C for survival of inoculated Clostridium sporogenes spores and Listeria monocytogenes. Clostridia and listeriae survived one cooking when surface inoculated and two cookings in roasts inoculated internally. Lactate in brine afforded protection against clostridial survival and growth in temperature-abused roasts. Clostridia grew after 24 hr at 25°C in untreated roasts cooked once, and after 48 hr of abuse in most others except those with lactate or monolaurin. Listeria survival was reduced by lactate and monolaurin in recooked surface-inoculated roasts.     

Effect of domestic cooking on the red cabbage hydrophilic antioxidants

The contents of vitamin C, total phenolics, anthocyanins, hydroxybenzoic and hydroxycinnamic acids as well as 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) monocation radical scavenging activity were evaluated in two varieties of red cabbage before and after conventional and steam‐cooking. During the conventional cooking 32.7–64.5% of vitamin C and 45.7–66.9% of total phenolics were retained in cooked tissue. Decreasing cooking water volume by half led to better retention of both phenolics (by 2.7–14.5%) and vitamin C (by 14.2–18.4%). However, shortening the cooking time by half affected the retention of phenolics and vitamin C only by 3.8–6.7% and 0–2.2%, respectively. Steam‐cooking is recommended to prevent the major loss of scavenging activity, because under these conditions, the corresponding TEAC (Trolox Equivalent Antioxidant Capacity) values were reduced only by 5–20%. Moreover, the content of vitamin C was decreased by 2.1–22.7% while losses of total phenolics were up to 10%. The phenolics are the major source of free radical scavenging activity of red cabbage, since the contribution of vitamin C to TEAC for fresh and cooked red cabbage was from 18.2 to 28.5%.     

Vacuum-Packaged Precooked Pork from Hogs Fed Supplemental Vitamin E: Chemical, Shelf-Life and Sensory Properties

Precooked longissimus chops and semimembranosus/adductor roasts from pigs (n = 30) given no supplemental vitamin E (CON) or supplemented with 100 mg vitamin E/kg diet (VITE) were evaluated for lipid oxidation, microbial growth, sensory characteristics, cooking/storage losses and reheating losses. Chops and roasts were vacuum packaged, precooked to 60°C and stored at 2°C for 0, 7, 14, 28, or 56 days. Lipid oxidation was lower in VITE chops and roasts than in CON chops and roasts. Off-flavor intensity scores were more acceptable and storage/ cooking losses were lower for VITE roasts than for CON roasts. Supplementation of vitamin E in a swine diet provided added protection against lipid oxidation and precooking pork under vacuum provided a palatable product with a shelf-life of 56 days.     

The effects of packaging method (vacuum pouch vs. plastic tray) on spoilage in a cook-chill pork-based dish kept under refrigeration

The effects of two packaging methods on the spoilage of a cook-chill pork-based dish kept under refrigeration were studied. Raw pork cuts and pre-cooked tomato sauce were packed under vacuum “sous vide” in polyamide–polypropylene pouches (SV) or into translucent polypropylene trays under modified atmosphere (80% N₂ + 20% CO₂) and sealed with a top film (PT). Samples were cooked inside the pack at an oven temperature/time of 70 °C/7 h, chilled at 3 °C and stored at 2 °C for up to 90 days. Microbial (psychrotrophs, lactic-acid bacteria, Enterobacteriaceae, moulds and yeasts), physical–chemical (pH, water activity and total acidity) and sensory (colour, odour, flavour, texture and acceptance) parameters were determined. Heat penetration was faster in SV (2 °C/min) than in PT (1 °C/min) (core temperature). Both packaging methods were equally effective in protecting against microbial spoilage for 90 day at 2 °C. Minor counts were only detected for lactic-acid bacteria and anaerobic psychrotrophs in SV. No Enterobacteriaceae growth was found. Slight differences between SV and PT in pH and total acidity were observed. SV and PT had similar effects on the sensory preservation of the dishes. A gradual loss of acceptance of the cooked pork and tomato sauce was observed. Rancid flavour in PT and warmed-over-flavour in SV were noted in the final stages of storage. According to acceptance scores, the shelf-life of both SV and PT was 56 days at 2 °C. Both packaging methods can be used to manufacture sous vide meat-based dishes subsequently stored under refrigeration for catering use.     

Effect of Cooking Method,Distiller's Grains,and Vitamin E Supplementation on the Vitamin Content of Value Cuts from Beef Steers Fed Wet Distiller's Grains and Solubles and Supplemental Vitamin E

ABSTRACT: Vitamin E, thiamin, riboflavin, niacin, vitamin B₆, and vitamin B₁₂ concentrations of flat iron steaks and petite tenders from steers fed finishing rations containing 0% and 40% corn wet distiller's grains and solubles (WDGS) with and without supplemental vitamin E were determined. Feeding treatment groups were: 0% WDGS with basal vitamin E, 0% WDGS with supplemental vitamin E (500 IU daily), 40% WDGS with basal vitamin E, and 40% WDGS and supplemental vitamin E. Cattle can be fed 40% WDGS diets more economically than corn diets. The incorporation of 40% WDGS, with and without vitamin E, was hypothesized to have little effect on the vitamin concentrations of these value meat cuts. Flat iron steaks and petite tenders were broiled and/or grilled to 70 °C internal temperature. Mean cooking yields ranged from 68.7% to 78.2%. The majority of the vitamin concentrations of broiled and of grilled meat were significantly different (P < 0.05) from that of raw meat. Vitamin E concentrations of raw and cooked meat from steers that received supplemental vitamin E were significantly higher (P < 0.05) than those fed basal vitamin E. Significant differences in thiamin, riboflavin, vitamin B₆, and vitamin B₁₂ concentrations in raw flat iron steaks and in vitamin B₆ in raw petite tenders were observed by WDGS. Thiamin, vitamin B₆, and vitamin B₁₂ concentrations of broiled flat iron steaks were significantly different (P < 0.05) than grilled. A few differences in vitamin concentrations of the flat iron steaks and petite tenders were observed by WDGS, vitamin E supplementation, and cooking treatments, but most of the vitamin concentrations were statistically similar.     

An Approach to Safe Microwave Cooking of Pork Roasts Containing Trichinella spiralis

Pork roasts, obtained from pigs experimentally infected with Trichinella spiralis, were cooked at 50% power in four microwave ovens. The attainment of consistently well done roasts is the primary requisite for development of safe cooking methods. Recommendations for cooking of trichinous pork roasts, with adequate margins of safety, are made for each oven.