Digital Commons Network^™

Orange Juices Enriched With Chitosan: Optimisation For Extending The Shelf-Life, Catherine Barry-Ryan, Ana Belen Martin-Diana, Daniel Rico, J. Barat

Articles

Optimisation of the incorporation of chitosan in orange juice was accomplished by the evaluation of quality and nutritional markers. Response surface methodology was applied to obtain quadratic and second degree response surface model equations. The analyses showed that increases in chitosan concentration extended the quality of the orange juice significantly (p < 0.05), reducing enzymatic and non-enzymatic browning and controlling the spoilage during the storage time; however, concentrations N 1 g L− 1 produced a significant (p < 0.05) reduction in the concentrations of ascorbic acid and carotenoids associated with the positive charge of chitosan and its ability to flocculate and coagulate negatively charged substances. Also, concentrations N 1 g L− 1 were scored as unacceptable for the sensory panel due to an increase in bitterness. The study recommends the use of chitosan at concentrations up to 1 g L− 1 to extend quality and preserve ascorbic acid and carotenoids during storage time of fresh orange juice, thus avoiding the use of standard thermal treatments which produces a negative impact on the nutritional value. Industrial relevance: One of the major problems of fresh orange juice is its limited shelf-life. Spoilage and quick degradation of vitamins are two of the most important causes of quality loss during the shelf-life of this product. Moreover, the U. S. Food and Drug Administration issued a warning to consumers against drinking unpasteurised orange juice products because of the potential contamination with Salmonella typhimurium and its association with an outbreak of human disease caused by this organism [FDA issues nationwide health alert on Orchid Island unpasteurised orange juice. Products Recalls, Market Withdrawals and Safety Alerts.]. The main objective of this study was the study of chitosan as a natural preservative for extending the shelf-life of orange juice and as an alternative to pasteurisation.

Quality Function Deployment During Industrial Chocolate Manufacture, Emmanuel Ohene Afoakwa

Professor Emmanuel Ohene Afoakwa

No abstract provided.

Effects Of Tempering And Fat Crystalization Behaviours On Microstructure, Mechanical Properties And Appearance In Dark Chocolate Systems., Emmanuel Ohene Afoakwa, Alistaiar Paterson, Mark Fowler, Joselio Vieira

Professor Emmanuel Ohene Afoakwa

Fat crystallisation behaviours in dark chocolates from varying particle size distribution (PSD) (D90 of 18, 25, 35 and 50 µm) was studied, yielding products from different temper regimes (optimal temper, over-temper and under-temper), and their effects on mechanical properties and appearance evaluated. Microstructures of derived products were determined using stereoscopic binocular microscopy. Wide variations in mechanical properties and appearance were noted in products from different particle size and temper regimes. Particle size (PS) was inversely related with texture and colour, with the greatest effects noted in hardness, stickiness and lightness at all temper regimes. Over-tempering caused significant increases in product …

Use Of Neutral Electrolysed Water (Ew) For Quality Maintenance And Shelf-Life Extension Of Minimally Processed Lettuce, Daniel Rico, Ana Belen Martin-Diana, Catherine Barry-Ryan, Jesus Maria Frias, Gary Henehan, José Barat

Articles

Experiments were conducted to determine the effectiveness of different treatments based on the use of neutral electrolysed water (EW) on fresh-cut lettuce. EW was diluted to obtain different free chlorine concentrations (120, 60 and 12 ppm) and compared with standard washing treatment of 120 ppm chlorine solution. Shelf-life quality and safety markers were studied at the beginning and at the end of the 7-day storage at 4 ºC. The use of EW decreased the respiration rate of the samples which might be related with the observed reduction in microbial spoilage. The use of EW also increased the activity of a …

Optimisation Of Steamer Jet-Injection To Extend The Shelf Life Of Fresh-Cut Lettuce, Daniel Rico, Ana Belen Martin-Diana, Catherine Barry-Ryan, Gary Henehan, J. Barat, Jesus Maria Frias

Articles

Optimisation of short time blanching (steaming) was investigated using response surface methodology by analysing quality and microbial and nutritional markers over the shelflife of packaged fresh-cut lettuce. Steamer treatment time (5–10 s) and storage (1–10 days) were used as independent factors in order to optimise the process. Longer treatments (>10 s) were not feasible because of extensive damage caused to lettuce tissue. Significantly (p < 0.05) higher values of luminosity (L*), greenness (−a*) and sensory panel scores (fresh appearance, general acceptability and absence of browning) were obtained with samples treated for longer times with the steamer. Activity of browning-related enzymes present in photosynthetic tissue decreased in all the cases, however, longer treatment time (7.5–10 s) was needed with vascular tissues to reduce to similar activity values. These differences could be explained by the variation in tissue thickness. The longest steam treatment (10 s) reduced and maintained significantly (p < 0.05) lower mesophilic load than shorter treatments (5–8.5 s). However, significant (p < 0.05) decreases in vitamin C and carotenoids were observed in samples treated with longer treatments. Steamer treatment of 10 s could be considered the optimum time for maintaining the shelflife (mainly texture and browning) of fresh-cut lettuce for 7–10 days in optimum conditions.

Extending And Measuring The Quality Of Fresh-Cut Fruit And Vegetables: A Review, Catherine Barry-Ryan, Ana Belen Martin-Diana, Daniel Rico, J. Barat

Articles

The market sales of ready-to-use fresh vegetables have grown rapidly in recent decades as a result of changes in consumer attitudes, especially consumption of fresh-cut lettuce and carrot due to their use in prepared salads. Chlorine solutions have been widely used to sanitise fruit and vegetables in the fresh-cut industry. However, the association of chlorine with the possible formation of carcinogenic chlorinated compounds in water has called into question the use of chlorine in food processing. There is a real need to find alternatives for preservation of fresh-cut fruit and vegetables in order to improve the efficacy of washing treatments. …

1% Calcium Chloride Treatment In Combination With Gamma Irradiation Improves Microbial And Physicochemical Properties Of Diced Tomatoes, Anuradha Prakash, Pei-Chen Chen, Richard L. Pilling, Nicole Johnson, Denise Foley

Food Science Faculty Articles and Research

The purpose of this study was to determine the effect of a combination of a 1% calcium chloride dip with low dose irradiation on microbial populations, and biochemical and physical properties, of fresh diced tomatoes during a two-week storage period. Vine tomatoes at the light-red stage (trial 1) and Celebrity tomatoes at the table ripe stage (trial 2) were diced, dipped in 1% CaCl2, and irradiated at 1 kGy from a Co-60 source. Tomatoes were also contaminated with cocktail of nalidixic-acid resistant Salmonella strains (S. Poona, S. Hartford, S. Gaminara, S. Michigan, and S. Montevideo) and subjected to gamma irradiation. …

Irradiation D Values Of Salmonella Spp. In Diced Tomatoes Dipped In 1% Calcium Chloride, Anuradha Prakash, Nicole Johnson, Denise Foley

Food Science Faculty Articles and Research

Outbreaks of salmonellosis have been associated with eating raw domestic tomatoes. In this study, we examined the efficiency of combined irradiation and a 1% calcium chloride dip to reduce the population of Salmonella enterica strains on diced tomatoes. Tomatoes were contaminated with nalidixic acid-resistant strains of S. Hartford, S. Montevideo, or a mixture of 5 strains (S. Hartford, S. Montevideo, S. Poona, S. Michigan, S. Gaminara). We irradiated tomatoes at various doses up to 0.9 kGy from an electron beam source to conduct a D-value study (decimal reduction time required to eliminate 90% of the organism). Surviving Salmonella populations were …

Efficacy Of Steamer Jet-Injection As Alternative To Chlorine In Fresh-Cut Lettuce, Ana Belen Martin-Diana, Daniel Rico, Catherine Barry-Ryan, Jesus Maria Frias, Gary Henehan, J. Barat

Articles

Short-time steam processing was used as an alternative to chlorine (100 mg L⁻¹) in sanitising fresh-cut lettuce. Quality (pH, water content, colour, potential browning, browning-related enzymes and texture), safety (mesophilic counts) and antioxidant markers (ascorbic and carotenoids) were monitored in lettuce stored for 10 days at 4 °C. The steam treatment produced a shocking effect on lettuce metabolism, showing a significant (p < 0.05) reduction in respiration (from day 3 to 7) and a partial inactivation of browning-related enzymes. Both effects were reflected in a significant reduction of browning. From a safety point of view, steam treatment kept the mesophilic load as low as chlorine treatment, and significantly lowers than the water control. However, antioxidant content, especially ascorbic acid but also carotenoids in a lower degree, showed a reduction compared with chlorine-treated samples. Despite the lower visual browning in steam-treated samples, the sensory panel scored similar values of acceptability and fresh appearance for both samples similarity.

Optimisation Of Calcium Lactate Washing Treatment On Salad-Cut Lettuce: Quality Aspects, Ana Belen Martin-Diana, Daniel Rico, Catherine Barry-Ryan, Jesus Maria Frias, Jemina Mulcahy, Gary Henehan

Articles

Markers of quality retention: colour, texture, browning, texture related enzymes and sensory properties, were analysed during storage. The use of high temperatures (50ºC) showed a positive effect on enzymes related to quality maintenance. It reduced the activity of the browning-related enzymes polyphenol oxidase and peroxidase but it increased the activity of pectin methyl esterase, an enzyme involved in the maintenance of texture. High calcium lactate concentrations (3 %) produced a reduction in the respiration rate of the salad-cut lettuce during storage, but also a loss of luminosity and greenness (a*). The use of high temperatures and intermediate calcium lactate concentrations …

Influence Of Storage Duration, Temperature, And Oxygen On Quality Of Stored Dehydrated Foods, Omima Ali Darag

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study was undertaken to determine the effect of oxygen absorber packets (OAP) (AGELESS Z.300 E) in improving the shelf-life of selected dried food products, including dried potato pearls, dried sliced apple, dried carrot, white rice, nonfat dry milk, all purpose flour, rolled oats, and wheat. Items were stored at four different temperatures (-20, 10, 21, and 29.5°C) over a period of 24 months with observations at 6-month intervals. Hunter colorimeter, thiobarbituric acid reactive substance (TBARS) germination rate, gluten weight, and volume were parameters used as quality indicators of various dried foods.

Statistical analysis indicated a significant time and temperature …

Magnetic Resonance Imaging Of Cheese Structure, M. Rosenberg, M. J. Mccarthy, R. Kauten

Food Structure

Cheese quality and quality evaluation are important in the production and marketing of cheeses. The commercial value and acceptability of bard and semi-bard cheeses are greatly affected by the cheese structure and body features. This is a feasibility study using magnetic resonance imaging (MRI) techniques to evaluate cheese structure.

The results indicate that MRI is a non-destructive method which can provide high resolution images of the inner structure of cheeses, particularly the presence of air and whey pockets as small as 0.1 x 0.1 x I mm. It may be used to study and evaluate eye structure, size, and distribution …

Effect Of Proteolytic Activity Of The Lactic Cultures On Mozzarella Cheese Quality, Wen-Hsu Amos Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Mozzarella cheese market is growing rapidly. Major concerns with cheese meltability and color have arisen in the fast food industry. Pre starter culture was used in this study to improve the physical properties of Mozzarella cheese. Three tests (stretch test, melt test, and browning test) were modified to evaluate the quality of cheese.

A stretch test using the Brookfield helipath viscometer to stretch the cheese sample at 60°C was successful in distinguishing cheeses from different make procedures and from different proteolytic strains. A melt test using a glass tube to hold the cheese flow at 110°C for 60 min …

Past, Present, And Future: The Food Service Industry And Its Changes, Herman E. Zaccarelli Brother

Hospitality Review

In the article - Past, Present, and Future: The Food Service Industry and Its Changes - by Brother Herman E. Zaccarelli, International Director, Restaurant, Hotel and Institutional Management Institute at Purdue University, Brother Zaccarelli initially states: “Educators play an important role in the evolution of the food service industry. The author discusses that evolution and suggests how educators can be change agents along with management in that evolutionary progression.”

The author goes on to wax philosophically, as well as speak generically about the food service industry; to why it offers fascinating and rewarding careers. Additionally, he writes about the influence …

Scanning Electron Microscopy Of The Pericarp And Testa Of Several Sorghum Varieties, C. F. Earp, L. W. Rooney

Food Structure

Pericarp thickness (determined by Z gene) varies greatly among sorghum varieties ranging· from very thin (8 ~ m) to very thick (160 ~m ) . Pericarp thickness also varies within an individuual kernel. The areas below the style and near the hilum are the thickest with the sides of the kernel being thinnest . Scanning electron microscopy was used to document differences in pericarp thickness and to explain milling differences . Varieties with a thick pericarp had starch granules in the mesocarp cell layers. Sorghums with a thin pericarp did not have starch granules in the mesocarp except near the …

Comparison Of Skim Milk Starter, Whey Base Starter And A Direct Set Method On The Yield, Quality And Economics Of Cottage Cheese Production, Wayne G. Geilman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three different methods of acidifying skim milk(milk starter, whey base starter and direct acid set) for making cottage cheese were evaluated for their effect on yield, quality and acidification cost. Cultured cottage cheese was produced with milk starter and pH controlled whey-base starter by the short set method. Five percent milk starter and 2.4% whey base starter were approximately equivalent in activity and gave average setting times of 234 to 255 minutes. Direct acid set cottage cheese was made by the Vitex/American method. The setting time required for direct acid set cottage cheese was 158 minutes. Yields of cottage cheese …

Energetics Of Home Dehydration; The Effect On Product Cost And Quality, Crystal Ann Willis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was two-fold: (1) to compare different home dehydrators and determine if the operation and design of the home dehydrators affected the color, cost, nutrient content, acceptability or flavor of the resulting products and (2) to determine the effect of physical parameters on product color, nutrient content, acceptability and flavor. The physical parameters that were measured during the dehydration process were temperature, relative humidity, and mass flow rate of air. Two products, Daucus carota var sativa (carrot) and juice of Lycopersicon sp. (tomato), were dried in each of six dehydrators (treatments). A sensory panel was used …

Judging Quality In Dairy Products, P. A. Downs

Nebraska Agricultural Experiment Station: Historical Circulars

In the dairy industry increasing attention is being paid to the question of quality of products. The well established system of buying and selling butter and cheese on the basis of quality by score or grade is practiced in the principal markets of the world. The other dairy products, while not marketed by score, are receiving more and more attention in this respect. As more information becomes available and the judging better standardized, other dairy products will doubtless be sold by grade.