Nonthermal pasteurization of pitaya (Hylocereus polyrhizus) juice using the hurdle concept

Red pitaya juice (RPJ) was subjected to UV-C irradiation and the potential of UV as a pasteurization tool for reducing microbial load in pitaya juice was evaluated. Effectiveness of the hurdle concept, i.e. addition of citric acid (CA) and dimethyl dicarbonate (DMDC) was also studied. Total plate counts (TPC) and yeast and mould counts (YMC) achieved 2.43 log10 and 2.7 log10 reductions respectively after exposure to UV irradiation. Addition of the CA (0.5-2.0%) and dimethyl dicarbonate (DMDC) (5-20 μL/100mL) to pitaya juice reduced the microbial loads, with 1.5% CA and 15 μL/100mL DMDC being the most effective concentrations. Addition of CA and DMDC into RPJ prior to UV treatment achieved significantly higher microbial reduction compared to UV alone, which were 4.12 log10 and 4.14 log10 reductions for TPC and for YMC, respectively

Effect of thermal and ultraviolet treatments on the stability of antioxidant compounds in single strength pineapple juice throughout refrigerated storage

Thermal treatment is commonly applied in juice manufacturing as a method to pasteurize juices. However the heat may deteriorate some of the essential compounds in the juice, especially heat-sensitive antioxidants. Therefore non-thermal treatment such as ultraviolet (UV) ray has been proposed as an alternative for pasteurization. The objective of this study was to compare the effect of thermal and UV treatments on the content of antioxidants (phenolic acids, flavonoids, carotenoids, ascorbic acids) and antioxidant capacity of single strength pineapple juice. The antioxidants stability of juices throughout 14 days of refrigerated storage was also studied. Ultraviolet treatment shows higher ascorbic acid content after treatment as compared to thermally treated single strength pineapple juice. Storage time affected the studied antioxidants, where UV treatment provided better stability to ascorbic acid content while thermal treatment provided better stability to flavonoids and carotenoids

Formulation and process improvement for chili shrimp paste using sensory evaluation

This study was conducted to improve the formulation of chili shrimp paste (CSP) based on sensory evaluation in terms of acidity, source of acid and coarseness of chili paste and to improve the production process of CSP. The effectiveness of dimethyl dicarbonate (DMDC) as a microbial reduction agent was also evaluated. To produce CSP with different coarseness, a milling machine was used. Two types of preference test were conducted, i.e. ranking and hedonic. The preferred pH level was 4.0, the best acid source was kalamansi juice, and the most preferred coarseness for chili paste was when milling plates with a gap of 120 μm was used. DMDC has no effect on microbial reduction due to the presence of fat globules in CSP which hindered the inactivation action. Milling can substitute pounding as it is much faster and can produce a uniform CSP with higher volume

Development of instrumental methods for textural evaluation of chili paste

Chili shrimp paste (CSP) is a traditional Southeast Asian condiment. It is a semi solid suspension that contains chunky chili pieces. The textural characteristics of the paste are important quality parameters for most CSP lovers because they prefer pastes with a certain degree of thickness and chunkiness. Unfortunately, there is no standard methodology available to evaluate the textural properties of these pastes. Various samples of CSP were prepared and evaluated using sensory, texture analyzer and rheometer measurements. The results from instrumental evaluation were consistent and comparable to sensory data. Texture analysis using the back extrusion method (spherical probe and cylinder) was found to be suitable for textural quantification of CSP. The tan δ values measured using a vane-in-a–large-cup rheometer using an oscillation frequency sweep at 20 Hz correlated well with the sensory results, indicating that this method could effectively distinguish differences in CSP samples with different rheological properties . Both instrumental methods can be applied as quality control tools for CSP products

Pineapple juice production using ultraviolet pasteurisation: potential cost implications.

Urban lifestyles have contributed to consumers’ need for convenient and nutritious food products. This study is aimed at determining the cost implications of pineapple juice production using ultraviolet (UV) as an alternative (non-thermal technology) to the conventional pasteurisation methods used in small-medium scale juice facilities in Malaysia. The financial analysis involved Contribution Margin, Net Present Value, Payback, Period, and Profitability Index of the UV and heat treated pineapple juices. Ultraviolet pasteurisation has relatively lower initial capital development cost than heat pasteurisation. Thus, implementation of UV technology can be more profitable than heat treatment when applied in a small-medium scale pineapple juice processing plant

Physicochemical properties and volatile profile of chili shrimp paste as affected by irradiation and heat

Chili shrimp paste (CSP) is an exotic traditional Southeast Asian condiment prepared using mainly fresh chilies and fermented shrimp paste (belacan) which attributed to strong pungent fishy odor. This study aims to evaluate the effectiveness of electron beam irradiation (EBI) exposure on CSP for microorganisms decontamination, and its physicochemical qualities changes. Changes in capsaicinoid contents and volatile compounds were analyzed using HPLC and GC–MS. Mesophilic bacteria, yeast, mold and pathogenic Enterobacteriaceae decreased as irradiation dose increasing from 0 to 10 kGy. EBI at 10 kGy effectively decontaminated the samples with no significant effects on phenolic and capsaicinoids contents compared to the fresh samples. From 24 compounds, irradiated CSP retained 23 volatile compounds, while thermally treated CSP has only 19 compounds. EBI at 10 kGy is effective for decontamination in CSP with lesser destructive effect on volatile compounds and texture compared to thermal treatment

Formulation improvement, process development, and quality assessment of chili shrimp paste

Chili shrimp paste (CSP), also known as sambal belacan in Malaysia, is wellliked in many Southeast Asian countries and is recognized as a national heritage food by the Malaysian Ministry of Cultural Arts and Heritage. This savory condiment is prepared by pounding fresh chilies with a small amount of fermented shrimp paste in stone mortar. No standard formulation or safety regulations have yet been developed for this product which could be used as a reference in food industries. It is usually prepared fresh, just before serving due to its perishable nature. In addition, pounding the chili in mortar to get the desired texture is a tiring job. This study was conducted to improve formulation, assess quality and develop processing methods for CSP. Results indicated that a typical product preferred by panelists contains approximately 70% moisture content, 27°Brix, 4.4% total salt content, 10% sucrose content, thick and chunky paste withlightness value (L) of 23, redness value (a) of more than 20 and yellowness value (b) of 12. The instrumental methods developed included texture analysis using the back extrusion (sphere and cylinder) and the rheometer using an oscillation frequency sweep (vane in large cup) were found suitable to evaluate textural and rheological quality of CSP. Pastes prepared using an electrical stone mill with parallel plates (120 μm gap) had textural and rheological characteristics similar to the traditionally prepared products. Samples with acceptable textural properties were tested for its rheological behavior in the temperature range of 25-85 °C. Shear stress-shear rate data were adequately fitted to rheological models, i.e. Power law, Bingham plastic, Herschel-Bulkley, Casson and Mizrahi and Berk models, with the Casson being the most fitted (R2 = 0.981) model. The tested paste showed non-Newtonian shear thinning behavior as the flow behavior index was less than one. Experimental yield stress values were different from those calculated using models, thus it is more accurate to determine yield stress from experiments. The defined flow behavior of CSP will allow engineers to design industrial process equipment. Thermal process (80 °C, 21.6 min) was effective and reliable in controlling microorganisms and deactivate the peroxidase as a deteriorative enzyme. In contrast, physicochemical and sensorial properties of CSP were negatively affected by heating. Electron beam irradiation (10 kGy) as an alternative non-thermal processing method was able to effectively control the microorganisms in CSP. Despite insignificant reduction in peroxidase activity and destructive effect on texture, irradiation was a better tool compared to thermal treatment in preserving phenolics, capsaicinoids, color and flavor of CSP. Inconclusion, this study provided improved formulation and quality control method for textural anlysis of CSP. In addition,preliminary data for scaling up of CSP in commercial setup was obtained. Irradiation was a better processing method than thermal processing for preserving the quality of the product. Findings of this research will help future industrial implementation of commercialized CSP to meet consumer demands

Microbial and quality attributes of thermally processed chili shrimp paste

Chili shrimp paste (CSP) is a favorite condiment in Southeast Asia. Microbial spoilage makes CSP unsuitable for consumption within several days. Thermal treatment was applied to produce microbiologically safe CSP. The effect of heating process on physicochemical and sensorial properties of CSP was studied. Heating at the optimum condition (21.6 min, 80 °C) has been shown effective and reliable in controlling microorganisms in CSP. Complete inactivation of peroxidase activities could not be accomplished at the optimal point, and significant reduction of the total phenolic and capsaicinoids contents was observed. Sensorial evaluation indicated that thermally processed CSP was less preferred by panelists when compared to freshly prepared samples of dry weight respectively

Physicochemical and sensory properties of a traditional chilli shrimp paste.

Chilli shrimp paste is a traditional Southeast Asian condiment, usually consumed uncooked as a side dish with meal or raw vegetables. Chilli shrimp paste conventionally is prepared by housewives at home or at the restaurants using toasted fermented shrimp and fresh red chillies which are ground together with a granite mortar and pestle. The physicochemical properties and consumer preference of different chilli shrimp pastes were determined. The analyses were carried out using products obtained from the hypermarkets (commercially processed), restaurants (fresh made), and a product made in the laboratory by a professional chef. The colour value, pH, total soluble solids, moisture content, salt and sucrose were investigated. The results indicated that chilli shrimp paste with approximately 70% moisture content, 27 °Brix, 4.4% salt, 10% sucrose, thick and chunky paste with lightness value (L) of 23, redness value (a) of more than 20 and yellowness value (b) of 12 was more preferred. The linear model was found to describe the correlation between panellist score and colour values. Based on the model, panellists like redness and lightness but not yellowness. The highest coefficient of (a) value shows the most effective factor in colour score by panellist was redness. The pH range of samples was from 4.02 to 6.33. The pH of the samples did not affect the preference. Chilli shrimp paste prepared in the laboratory was most preferred while the commercially processed product was least preferred. The provided information in this study will help those in the food service industry to improve their products to meet consumer demand

Texture Evaluation for a Commercial Chili-Based Paste

Chili shrimp paste (CSP) is a traditional Southeast Asian condiment conventionally prepared using a granite mortar and pestle. It is a semi-solid suspension which contains chunky chili pieces. Textural characteristics of the pastes are important quality parameters for consumers as they prefer pastes with a certain degree of thickness and chunkiness. Unfortunately, there is no standard methodology available to evaluate textural properties of such pastes. The objectives of this study were to establish a method for size reduction of chilies suitable for commercial production of CSP and to determine the typical textural properties of CSP preferred by consumers. Various samples of CSP were prepared and evaluated through sensory and instrumental evaluations (back extrusion method and vane in cup). Chili shrimp pastes prepared using the super mass colloider can substitute traditional pastes prepared by manual pounding in mortar. The milled CSP can produce a uniform paste, similar to the traditionally mortar pounded CSP samples but with the advantage of a higher production capacity. Both instrumental (textural measurement) methods were found to be reliable and consistent methods which can be applied in quality control for textural properties of CSP in a commercial-scale production set-up