Modelling the kinetics of osmotic dehydration of mango: Optimizing process conditions and pre-treatment for health aspects

The kinetics of mass transfer and vitamin C loss in mango during osmotic dehydration (OD) were described by mathematical models. Water loss (WL) and weight reduction (WR) was modelled by Weibull's model, soluble solid gain (SSG) was better described by Peleg's model. Vitamin C loss was described by a multiresponse model incorporating both degradation and leaching processes into the OD-solution. Effects of vacuum impregnation (VI) and pectin methylesterase (PME) addition on the model parameters were evaluated. VI increases SSG indicated by a 55% lower value of k2 in the Peleg model (P < 0.05). PME addition showed no significant effect on the mass transfer kinetics. The major mechanism of vitamin C loss during OD was degradation. The pretreatments have no significant effect on degradation and leaching rate constants of vitamin C. The combination of modelling the mass transfer and vitamin C retention was shown to be valuable in optimizing the OD process design to enhance the health-promoting value of OD mango (sugar content, vitamin C) and processing time.</p

TINGKAT KEEFEKTIFAN LACTOPEROXIDASE SYSTEM (LPS) UNTUK MEMPERPANJANG LAMA SIMPAN SUSU SEGAR

Fresh milk is high risk food since it is susceptible to microorganism spoilage. Without appropriate handling, fresh milk will spoil in short time. Lactoperoxidase is an enzyme that in its nature in milk was not an antibacterial, but can be activated to be an antibacterial. The method is used to activate lactoperoxide for milk preservation known as lactoperoxidase system (LPS). This experiment aims to identify LPS effectiveness in two different temperatures. Fresh milk sample, obtained from Nyatnyono Village, Ungaran Central of Java. Fresh milk storage duration was compared between milk without LPS in room temperature (25-28oC), milk without LPS in refrigerator temperature (5-10oC), milk with LPS in room temperature, and milk with LPS in refrigerator temperature. The total bacterial cells (TPC), Salmonella count ,and Eschericia coli count, and pH were examined. Total bacteria in all treatments were increased, except in LPS at refrigerator temperature that have storage duration until 20 hours. In the all of treatments, Salmonella counts were increased rapidly except in milk with LPS at refrigerator temperature that have storage duration until 8 hours. However, E. coli could growth well in all treatments during storage. The pH value can be kept below 6 in all treatments, except in milk without LPS at room temperature. Keywords: effectiveness of lactoperoxidase system, storage duratio

The Quality Changes of Black Tiger Shrimp (Penaeus monodon) During Handling By Seafood Service Establishments

Shrimp is very perishable and have a very limited shelf-life. Thus, appropriate handling during post-harvest is very crucial in order to extend the freshness and shelf-life of shrimp. Moreover, good handling also can prevent shrimp from pathogenic microorganism contamination, which may cause food poisoning. Shrimp is one of favorite seafood sold in various kinds of food service, starting from street vendors to restaurants. Each food service has different behaviors regarding seafood handling. The aim of this study was to evaluate the quality changes in black tiger shrimp during handling in different seafood service establishments in Semarang. Behavior of shrimp handling in food services was observed at three street vendors and two seafood restaurants. The shrimp sampling were done at different handling steps in those food services, including at the arrival, after washing, and after storage. The quality changes of the shrimp during handling were assessed using sensory, physicochemical and microbial analysis. This study showed that during handling in both type of food services the acceptance of the shrimp decreased gradually due to its appearance and texture changes. Quality of shrimp was influenced by its quality at procurement step and the storage condition. Proper handling resulted in a decrease of microbial counts. The recommendation for improvement of the shrimp handling will also be discussed. The challenge for implementation of the improvement of shrimp handling is not only related to food handlers in food services, but also to other food supply chain actors, such as fishermen, sellers, and distributors. Food safety literacy and appropriate behaviors of all actors involved in shrimp supply chain are required. Keywords: shrimp, food service, handlin

Pengembangan Produk Jamur Kuping (Auricularia Auricula): Acar dan Keripik

Wood ear mushroom (Auricularia auricula) with its high fiber, springy texture and unique flavor is potential to be developed for high economical value processed food. This research aims to develop wood ear mushroom processed food, which are pickled mushroom and chips. The product development includes optimization of formulation and processing. The pickle was made in two brine concentrations (7,5% and 10%) and packed in Poly Ethylene (PE) plastic cups. During three weeks refrigeration, visual observation, the acidity level, color (using Chromameter CR 400 Konica Minolta) and total counts were measured weekly. For mushroom chips, there were five formulations of coating mixed flour (A: 100% wheat flour; B: 75% wheat flour : 25% rice flour; C: 75% wheat flour : 25% sagoo flour ; D: 50% wheat flour: 25% rice flour: 25% sagoo flour and E: 50% wheat flour : 50% sagoo flour). The chips were measured for the break strength (using Texture Profile Analysis by Loyyd Texture Analyzer), sensory evaluation (using hedonic ranking test) and proximate analysis. The result revealed that the recommended pickled mushroom was P10, which pretreated by soaking in 0.1% citric acid + 0.1% sodium metabisulfite and soaked in 10% brine solution since it has the longest shelf-life (two weeks in the refrigerator). Wood ear mushroom chips D which was coated with wheat flour: rice flour: sagoo flour 50%: 25%: 25% was the most preferred by the panelist

Consumer and technological insights for improving the quality of osmo-dehydrated mango

Processing of mango can alter consumers&rsquo; perception of the final dried mango quality. To optimize the dried mango quality by product and process design, consumer&rsquo;s insights on perceived product quality should be taken into account. The insights, which can consist of both product and process characteristics, should be transformed into useful input for designing food products. Previous consumer perception studies were focused on sensory, convenience and health aspects, and their interrelation with consumer perception, but less on that of process, particularly processing technology. No studies taking into account various drying technologies and the pre-treatments which can differently affect the intrinsic characteristics of dried mango and thus consumer perception. This thesis aimed at exploring insights from consumers and connecting them to technological optimization of the product quality during product and process design of dried mango. Exploration of consumers&rsquo; health perception across cultures and demonstration of its relevance for product and process design in the early stages of new product development was studied using dried mango as a case. A focus group approach was used with participants from three countries (The Netherlands, China, and Indonesia). Themes relating to health perception emerged, namely nutrition, naturalness, taste, and wellbeing, which were all expressed on different levels of abstractness. Participants&rsquo; health perception of dried mango varied and is related to the product category with which it is compared, e.g. candy or fresh fruit; and the eating context, e.g. position in the diet either as a snack or a meal. Additionally, it was shown that consumer insights in the health perception of a product not only relate to product characteristics but also processing and its characteristics. These insights were applied to product and process design through iterative interdisciplinary interactions between consumer scientists and food technologists. The transformation of consumers&rsquo; perception into technical product and process specifications was demonstrated through an illustrative example of two product concepts of natural dried mango. This result suggests that iterative interactions are necessary to obtain relevant product and process characteristics in the simultaneous design of the technical product and process specifications based on consumer perceptions. The perception of key intrinsic quality attributes and preferences of dried mango between consumers with different familiarity and health consciousness was further studied using an Adaptive Choice-Based Conjoint Analysis. This study involved respondents from three countries (The Netherlands, China, and Indonesia). Texture, taste and colour preferences of dried mango attributes differed between the three countries studied. The most important attribute for the Dutch and Chinese respondents was &lsquo;free from extra ingredients&rsquo; as they preferred a &ldquo;more pure&rdquo; mango product. While Indonesians considered texture as the most important attribute preferring a crispier dried mango product. Familiarity with dried mango and health consciousness do not influence consumer preference of intrinsic attributes of dried mango. Different preferences of intrinsic attributes of dried mango between the studied respondent groups are related to cultural differences. Effects of pretreatments with vacuum impregnation (VI) and high pressure (HP) and adding pectin methylesterase (PME) with calcium on the quality of osmo-dehydrated mango (Mangifera indica var. Kent) of different ripeness were studied. The use of unripe mango in OD showed two to five-fold higher soluble solid gain (SSG) compared to ripe mango for all treatments. Unripe mango pretreated with OD-VI showed the lowest water loss (WL) and the highest SSG. The OD-HP treatment had a similar but less pronounced effect as OD-VI on the parameters WL and SSG. The addition of the cell wall modifying enzyme PME increased OD efficiency for the treatments high pressure as well as vacuum impregnation, but only for ripe mango. Colour is an important quality attribute for dried mango. Overall, the applied settings for OD treatments appeared to be suitable for the preservation of the colour quality of mango. The hue (h*) values were generally preserved and colour intensity (C*) was maintained or only slightly increased in both ripeness in all treatments. Lightness (L*) was greatly reduced in unripe mango but stable in ripe mango. In general, adding PME increases a bit more effect on texture in terms of firmness and work of shear. This study thus demonstrates that using different ripeness of mango resulted in different quality of osmo-dehydrated mango upon pretreatments with calcium. As a follow-up study, the effects of vacuum impregnation (VI) pretreatment and PME addition on the kinetics of mass transfer and vitamin C loss was studied during osmotic dehydration of mango. The water loss (WL) and weight reduction (WR) were modelled by the Weibull&rsquo;s model, while soluble solid gain (SSG) was better described by Peleg&rsquo;s model. VI increases soluble solid gain (SSG) indicated by a 55% lower value of the equilibrium constant (k2) in the Peleg model. Vitamin C loss was described by a multiresponse model incorporating both degradation and leaching processes into the osmotic solution (OS). Degradation was found to be the most important mechanism during osmo-dehydration of mango. The pretreatments have no significant effect on degradation and leaching rate constants of vitamin C. The combined modelling of the mass transfer and vitamin C retention was shown to be valuable in optimizing the OD process design to improve the health-promoting value of OD mango (e.g. sugar content, vitamin C) and reduce the processing time. Furthermore, the results of this research highlight that taking into account both the consumer and technological insights is useful to optimize product and process design of dried mango with the desired quality

Consumer preference for dried mango attributes: A conjoint study among Dutch, Chinese, and Indonesian consumers

One way to add value to tropical fruit and increase its availability in the global market is to develop new, less perishable, products from fresh fruit. The purpose of this study is to compare the perception of key quality attributes and preferences of dried mango between consumers with different familiarity and health consciousness. This study surveyed respondents from China, Indonesia, and the Netherlands via an adaptive choice‐based conjoint method (n = 483) to evaluate intrinsic quality attributes that influenced consumer preference for dried mango. Consumers in different countries have different texture, taste, and color preferences for dried mango. The most important attribute for the Dutch and Chinese was “free from extra ingredients”, while for Indonesians, it was the texture. Familiarity with dried mango and health consciousness do not influence consumer preference of intrinsic attributes of dried mango. Different preferences of intrinsic attributes of dried mango between countries are related to cultural differences. This study provides useful insights for food manufacturers into the significance of key intrinsic quality attributes in developing dried mango

Osmotic dehydration of mango : Effect of vacuum impregnation, high pressure, pectin methylesterase and ripeness on quality

The effects of pretreatment with vacuum impregnation (VI) and high pressure (HP) and adding pectin methylesterase (PME) with calcium on the quality of osmotic dehydrated mango of different ripeness were investigated. Unripe and ripe ‘Kent’ mango cubes were osmotic dehydrated (OD at 50 °C in 60 °Brix sucrose solution containing 2 g calcium lactate/100 g and 0 or 0.48 mL PME/100 g), preceded either by VI (OD-VI) or HP (OD-HP). Use of unripe mango in OD showed two to five-fold higher soluble solid gain (SSG) compared to ripe mango for all treatments. Unripe mango pretreated with OD-VI showed the lowest water loss (WL) and the highest SSG. OD-HP had a similar but less pronounced effect as OD-VI on WL and SSG. Hue (h*) were generally preserved and color intensity (C*) were maintained or only slightly increased in both ripeness in all treatments. Lightness (L*) was greatly reduced in unripe mango but stable in ripe mango. In general, firmness and work of shear slightly increased when adding PME.</p

Exploring consumers’ health perception across cultures in the early stages of new product development: Dried mango as a case study

Purpose: The purpose of this paper is to explore consumers’ health perception and demonstrate its relevance in product and process design in early stages of new product development. Design/methodology/approach: A dried mango was used as a case study involving three countries: Indonesia, China and the Netherlands. Data were collected from nine focus groups (n=53 participants) and were content-analysed to acquire in-depth insights. Findings: Four themes of health perception emerged, namely, nutrition, naturalness, taste and well-being, which were all expressed on different levels of abstractness. Participants’ health perception of dried mango varied, it is related to the product category it is compared with, e.g. candy or fresh fruit, and the eating context, e.g. position in the diet either as a snack or a meal. In extension participants mentioned product and process characteristics. Application of the insights into product and process design was performed through iterative interactions between consumer scientists and food technologists. The development of two product concepts was elaborated to transform the insights into technical product and process specifications for a natural dried mango product. Originality/value: This transformation suggests that iterative interactions are necessary to achieve relevant product and process characteristics in the simultaneous design of the technical product and process specifications based on consumer perceptions.</p